| 1. |
|
|
| 2. |
- Lohmander, Stefan, et al.
(author)
-
Post-translational events in proteoglycan synthesis : Kinetics of synthesis of chondroitin sulfate and oligosaccharides on the core protein
- 1986
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861. ; 250:1, s. 211-227
-
Journal article (peer-reviewed)abstract
- Chondrocytes isolated from the Swarm rat chondrosarcoma were incubated in culture with [1-3H]glucose for 30 min to 8 h. Labeled proteoglycans were isolated, treated with borohydride under alkaline conditions, and the three complex sugar structures purified: N- and O-linked oligosaccharides and chondroitin sulfate chains. The amount of incorporated radioactivity into each component sugar was analyzed by HPLC after enzyme digestion and hydrolysis. The kinetic data for labeling of each sugar over the time course of the experiment were fit to first-order rate equations and the half times (t 1 2) to linear labeling were calculated. The t 1 2 values were essentially the same, 5-8 min, for galactose in all three complex sugar structures and for chain glucuronic acid in chondroitin sulfate, while that for xylitol in chondroitin sulfate, 15.8 min, was significantly longer. Thus, oligosaccharide synthesis is concomitant with chondroitin sulfate chain synthesis; the addition of the chondroitin sulfate linkage galactose occurs at or nearly at the same time as chain elongation while the addition of linkage xylose residues to the core protein may precede chain synthesis by up to 8 min. Since the intracellular t 1 2 of the core protein precursor for these cells is 45 to 90 min, the data strongly suggest that the addition of xylose is not completed to any significant extent while the polypeptide is still nascent or shortly after its release into the rough endoplasmic reticulum. It is proposed that the addition of xylose to the core protein precursor is a late endoplasmic reticulum or early Golgi event. The analytical data were consistent with the presence of ester phosphate on about 80% of the xylose residues of the newly synthesized proteoglycan.
|
|
| 3. |
- Lohmander, S., et al.
(author)
-
Secretion of proteoglycans by chondrocytes. Influence of colchicine, cytochalasin B, and β-d-xyloside
- 1979
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861. ; 192:1, s. 148-157
-
Journal article (peer-reviewed)abstract
- Chondrocytes obtained from epiphyseal cartilage of fetal guinea pigs or ear cartilage of young rabbits were cultured in monolayer. The influence of colchicine, cytochalasin B, and p-nitrophenyl-β-d-xylopyranoside on secretion of proteoglycans was investigated. Radioactive sulfate was used as a precursor. As observed previously in other systems, β-d-xylosides initiated the synthesis of free chondroitin sulfate chains, competing with the endogenous proteoglycan core protein acceptor. The molecular weights of the chondroitin sulfate chains synthesized both on the xyloside and on the core-protein acceptor in maximally stimulated cells were similar and significantly lower than in proteoglycans synthesized in the absence of xyloside. The size of the chondroitin sulfate chains synthesized on the xyloside was inversely related to the concentration of this compound. This finding suggests that the chain length is dependent on the ratio between available acceptor and chain-lengthening enzymes or precursors. Cytochalasin B, a microfilament-modifying agent, inhibited proteoglycan synthesis, without any effect on secretion. Cells treated with cytochalasin B could be stimulated with β-d-xyloside to synthesize free chondroitin sulfate chains to the same relative degree as cells with intact microfilaments. Colchicine, an antimicrotubular agent, partially inhibited synthesis and secretion of proteoglycan. However, cells treated with colchicine could be stimulated with β-d-xyloside to synthesize and secrete free chondroitin sulfate chains to about the same relative degree as cells with intact microtubules. The data suggest that microtubules may have a facilitatory rather than an obligatory role in the secretion of proteoglycans and that at least part of the effect of colchicine is located at or after the site of glycosaminoglycan synthesis.
|
|
| 4. |
- Lohmander, Stefan
(author)
-
Turnover of proteoglycans in guinea pig costal cartilage
- 1977
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861. ; 180:1, s. 93-101
-
Journal article (peer-reviewed)abstract
- The turnover in vivo of proteoglycans of guinea pig costal cartilage was investigated using Na2 35SO4 as precursor. Proteoglycans were extracted with guanidine · HCl, at both low and high ionic strength, and purified and fractionated by ultracentrifugation in CsCl gradients under associative and dissociative conditions. The results suggest that the sulfate is incorporated into macromolecules of at least two major metabolic pools with half-lives of about 3 days and about 60-70 days, respectively. Molecules with a fast turnover were enriched in the low ionic strength extracts and in fractions containing small, nonaggregated proteoglycans. No substantial evidence was found for a precursor-product relationship between different fractions.
|
|
| 5. |
- López Otin, C, et al.
(author)
-
The complete amino acid sequence of human complex-forming glycoprotein heterogeneous in charge (protein HC) from one individual
- 1984
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861. ; 228:2, s. 54-544
-
Journal article (peer-reviewed)abstract
- The complete amino acid sequence of the single polypeptide chain of human complex-forming glycoprotein heterogeneous in charge (protein HC) isolated from a single individual is reported with the supporting data. The primary structure was determined by automatic degradation of the intact chain and of fragments obtained by chemical and enzymatic degradations of the native or reduced and S-carboxymethylated protein. The polypeptide chain of protein HC contained 182 amino acid residues with a calculated molecular weight of 20,621. No amino acid sequence variability was found and such variability can therefore not explain the great charge heterogeneity of protein HC in a single individual. The amino acid sequence of protein HC was nearly identical to the one reported for human alpha 1-microglobulin in a research communication but contained 15 additional residues.
|
|
| 6. |
- Madsen, Kjell, et al.
(author)
-
Production of cartilage-typic proteoglycans in cultures of chondrocytes from elastic cartilage
- 1979
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861. ; 196:1, s. 192-198
-
Journal article (peer-reviewed)abstract
- Chondrocytes from rabbit ear cartilage were isolated and cultured as monolayers in Ham's F-12 medium. The proteoglycans synthesized by short-term cultures formed a high proportion of aggregates and contained chrondroitin-4- and -6-sulfate in a 2:1 proportion. Dermatan sulfate was not present. The average molecular weight of the chondroitin sulfate was about 20,000. Keratan sulfate with an average molecular weight of about 6000 could be isolated from the proteoglycan monomers. Rabbit ear chondrocytes in culture thus produced proteoglycans comparable to those isolated from hyaline cartilage. Culture for longer periods and plating at lower density caused a decrease in the proportion of aggregated proteoglycans. Primary cultures continued to synthesize aggregated proteoglycans for at least 2 weeks, while subdivision of the cultures caused a shift toward the production of small-sized "ubiquitous proteoglycans." The synthesis of proteoglycan aggregates could, however, be partly restored by transfer of the monolayer cells to a suspension culture.
|
|
| 7. |
- Mendez, E, et al.
(author)
-
Human complex-forming glycoprotein, heterogeneous in charge : the primary structure around the cysteine residues and characterization of a disulfide bridge
- 1982
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861. ; 213:1, s. 50-240
-
Journal article (peer-reviewed)abstract
- The amino acid sequence of the cysteine-containing regions of human complex-forming glycoprotein, heterogeneous in charge (protein HC) was determined by studies of the tryptic peptides of the completely reduced and radioalkylated protein. One of the cysteines was located in the amino-terminal part of the molecule at position 34....Diagonal map electrophoresis showed that the cysteine residue in the carboxy-terminal region was bridged to the cysteine containing sequence in the middle of the molecule. The function of the cysteine residue at position 34 remains elusive since the residue was not found on the diagonal maps. The release of cysteic acid and a small cysteic acid containing peptide after oxidation of the native protein HC molecule suggests that this cysteine residue may be involved in disulfide bridges with cysteine and small cysteine containing peptides.
|
|
| 8. |
- Sabharwal, Hemant, et al.
(author)
-
Oligosaccharides from feces of preterm infants fed on breast milk
- 1988
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861. ; 265:2, s. 390-406
-
Journal article (peer-reviewed)abstract
- Nine neutral and five acidic oligosaccharides were isolated from feces of a preterm (30th postmenstrual week) blood group A nonsecretor infant fed on pooled breast milk. Structural analyses were carried out using sugar and methylation analyses, fast atom bombardment mass spectrometry, and 1H NMR. The acidic oligosaccharides are well-known components of human milk. The neutral oligosaccharides are characteristic of nonsecretor milk. Surprisingly, no secretor gene-dependent oligosaccharides were present in the feces. Another preterm (27th postmenstrual week) blood group A, secretor infant fed on pooled breast milk showed the same fecal oligosaccharide pattern as above during the first week after birth, despite being a secretor individual. Also notable was the absence of blood group A-active oligosaccharides in this sample. Another sample of feces collected 8 weeks later from the latter infant contained the expected blood group A-active oligosaccharides. Furthermore, free sialic acid was present at the cost of the sialyl oligosaccharides seen earlier. Thus, infants born prematurely do not show the same degree of development of oligosaccharide metabolism as their more mature counterparts.
|
|
| 9. |
- Brodelius, Peter, et al.
(author)
-
Studies of Bovine Liver Glutamate Dehydrogenase by Analytical Affinity Chromatography on Immobilized AMP Analogs
- 1979
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861. ; 194:2, s. 449-456
-
Journal article (peer-reviewed)abstract
- Bovine liver glutamate dehydrogenase has been studied by analytical affinity chromatography on two immobilized AMP analogs, i.e., N6-(6-aminohexyl)-AMP and 8-(6-aminohexyl)-amino-AMP. The existence of various enzyme-coenzyme and enzyme-effector complexes has been verified. Also the cooperative formation of two ternary complexes, i.e., glutamic dehydrogenase (GHD)-NADP-glutamate and GDH-ADP-leucine, has been shown. The results of this study have been rationalized by the “ligand exclusion theory.” which has been proposed for the regulation of the glutamic dehydrogenase. It has been shown that the active site and the ADP-binding effector site are oriented close to each other on the enzyme. Furthermore, the data suggest that the adenylic site is not identical to the nonactive coenzyme binding site. A mechanism based on electrostatic interactions is suggested for the cooperative binding of oxidized coenzyme and substrate. Dissociation constants for complexes between the enzyme and two coenzyme fragments (P-ADPR and 2′,5′-ADP) have been estimated.
|
|
| 10. |
- Brodelius, Peter, et al.
(author)
-
The Synthesis of 8-(6-Aminohexyl)-Amino-GMP and Its Applications as a General Ligand in Affinity Chromatography
- 1978
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861. ; 188:1, s. 228-231
-
Journal article (peer-reviewed)abstract
- The synthesis of a new general ligand, i.e., 8-(6-aminohexyl)-amino-GMP, has been achieved by bromination of GMP and subsequent substitution of the bromine for hexamethylene diamine. The overall yield of the synthesis has been 60 to 70%. This new general ligand was immobilized on BrN-activated Sepharose and used as an affinity adsorbent for inosinic acid dehydrogenase (E.C. 1.2.1.14) from Aerobacter aerogenes. Various elution methods were investigated in order to increase the specific activity of the purified enzyme.
|
|
| 11. |
|
|
| 12. |
- Ekman, Pia, et al.
(author)
-
Phosphorylation of glucokinase from rat liver in vitro by protein kinase A with a concomitant decrease of its activity
- 1988
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861 .- 1096-0384. ; 261:2, s. 275-282
-
Journal article (peer-reviewed)abstract
- Glucokinase, purified from rat liver, was phosphorylated to an extent of 1 mol [32P]-phosphate/mol of enzyme when incubated with [32P]ATP and protein kinase A from pig or rabbit muscle. The phosphate was bound to serine residues. K0.5 increased and Vmax decreased upon phosphorylation. The phosphate group was removed during incubation of the phosphorylated glucokinase with alkaline phosphatase. Enzymatically inactive glucokinase was not phosphorylated by the protein kinase.
|
|
| 13. |
- Fernanda Troncoso, M., et al.
(author)
-
A novel trypsin inhibitor from Peltophorum dubium seeds, with lectin-like properties, triggers rat lymphoma cell apoptosis
- 2003
-
In: Archives of Biochemistry and Biophysics. - 0003-9861 .- 1096-0384. ; 411:1, s. 93-104
-
Journal article (peer-reviewed)abstract
- A trypsin inhibitor (PDTI) was isolated from Peltophorum dubium seeds by affinity chromatography on a thyroglobulin-agarose or a trypsin-agarose column. In both cases, SDS-PAGE showed two bands of M(r) 20,000 and 22,000, which could not be resolved. Their amino-terminal sequences were identical and similar to that of Kunitz-type soybean trypsin inhibitor (SBTI). Mass spectrometry analysis of tryptic digests of both bands showed 16 coincident peaks, suggesting that they are closely related proteins. The K(i)s for trypsin and chymotrypsin inhibitory activity of PDTI were 1.6 x 10(-7) and 1.3 x 10(-5)M, respectively. Lectin-like activity of PDTI and SBTI, detected by hemagglutination of rabbit erythrocytes, was inhibited by sialic acid-containing compounds. PDTI and SBTI caused apoptosis of Nb2 rat lymphoma cells, demonstrated by decrease of viability, DNA hypodiploidy, DNA fragmentation, and caspase-3-like activity. They had no effect on normal mouse splenocytes or lymphocytes, whereas they caused apoptosis of concanavalin A-stimulated mouse lymphocytes.
|
|
| 14. |
|
|
| 15. |
|
|
| 16. |
|
|
| 17. |
|
|
| 18. |
- Nilsson Ekdahl, Kristina
(author)
-
In vitro phosphorylation of fructose-1,6-bisphosphatase from rabbit and pig liver with cyclic AMP-dependent protein kinase
- 1988
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861 .- 1096-0384. ; 262:1, s. 27-31
-
Journal article (peer-reviewed)abstract
- Homogeneous preparations of fructose-1,6-bisphosphatase from mouse, man, rabbit, pig, and rat were tested as substrates for cyclic AMP-dependent protein kinase. Up to 1 mol of [32P]phosphate per mole enzyme subunit was incorporated into fructose-1,6-bisphosphatase from pig and rabbit liver, which should be compared with 2.6 mol of phosphate per mole enzyme subunit in the case of the rat liver enzyme. The phosphorylation of fructose-1,6-bisphosphatase from the livers of man and mouse was negligible. Phosphorylation of pig and rabbit fructose-1,6-bisphosphatase decreased the apparent Km for fructose-1,6-bisphosphate, but in contrast to the case of the rat liver enzyme it did not change the inhibition constants for AMP and fructose-2,6-bisphosphate. The Phosphorylation sites in rabbit and pig liver fructose-1,6-bisphosphatase were located close to the carboxyterminal of the polypeptide chains, since trypsin treatment of the phosphorylated enzyme quantitatively removed all of the protein-bound radioactivity without significantly altering the subunit molecular weight and with a maintained neutral pH Optimum.
|
|
| 19. |
|
|
| 20. |
- Persson, Bengt L., et al.
(author)
-
Energy-linked nicotinamide nucleotide transhydrogenase. Hydrodynamic properties and active form of purified and membrane-bound mitochondrial transhydrogenase from beef heart
- 1987
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861 .- 1096-0384. ; 259:2, s. 341-349
-
Journal article (peer-reviewed)abstract
- The mitochondrial nicotinamide nucleotide transhydrogenase from beef heart was investigated with respect to minimal assembly of the purified enzyme and of the enzyme in the mitochondrial inner membrane. Studies of the hydrodynamic properties of the purified enzyme in the presence of 0.3% Triton X-100 allowed determination of the Stokes radius, sedimentation constant, partial specific volume, frictional ratio, and molecular weight. Under these conditions transhydrogenase existed as an inactive monomer, suggesting that monomerization may be accompanied by inactivation. Radiation inactivation was used to determine the functional molecular size of purified detergent-dispersed transhydrogenase and transhydrogenase in beef heart submitochondrial particles. Under these conditions the catalytic activity of both the purified and the membrane-bound enzyme was found to be catalyzed by a dimeric form of the enzyme. These results suggest for the first time that the minimal functional assembly of detergent-dispersed as well as membrane-bound transhydrogenase is a dimer, which is not functionally associated with, for example, complex I or ATPase. In addition, the results are consistent with the possibility that the two subunits of transhydrogenase are catalytically active in an alternating fashion according to a previously proposed half-of-the-sites reactivity model.
|
|
| 21. |
- Pirpignani, María L., et al.
(author)
-
Structural and immunological aspects of Polybia scutellaris Antigen 5
- 2002
-
In: Archives of Biochemistry and Biophysics. - 0003-9861 .- 1096-0384. ; 407:2, s. 224-230
-
Journal article (peer-reviewed)abstract
- Vespid venoms contain Antigen 5, an important allergen whose primary structure and immunological behavior have been extensively studied from venoms of vespids of the Northern Hemisphere. We report herein structural and immunological aspects of Antigen 5 from Polybia scutellaris subspecies rioplatensis (vulgar name: camoati) found in South America. Mast cell degranulation, histamine release, and IgE induction experiments performed in mice allow us to suggest that P. scutellaris Antigen 5 is a variant with reduced IgE response and anaphylactic activity. Sequence data indicate that the protein has a 72.5-90.3% similarity to that of members of the vespid Antigen 5 family with an already known primary structure. Moreover, results suggest that the protein-a new member of an extracellular protein superfamily-could be a good candidate for immunotherapy related to vespid allergy.
|
|
| 22. |
- Stark, Katarina, et al.
(author)
-
Expression of CYP4F8 (prostaglandin H 19-hydroxylase) in human epithelia and prominent induction in epidermis of psoriatic lesions
- 2003
-
In: Archives of Biochemistry and Biophysics. - 0003-9861 .- 1096-0384. ; 409:1, s. 188-196
-
Journal article (peer-reviewed)abstract
- Our aim was to determine the tissue distribution of CYP4F8, which occurs in human seminal vesicles and catalyzes 19-hydroxylation of prostaglandin H(1) and H(2) in vitro (J. Bylund, M. Hidestrard, M. Ingelman-Sundberg, E.H. Oliw, J. Biol. Chem. 275 (2000) 21844-21849). Polyclonal antibodies were raised in rabbits against RVEPLG, the C-terminal end of CYP4F8, and purified by affinity chromatography. Screening of 50 human tissues for CYP4F8 immunoreactivity revealed protein expression, inter alia, in seminal vesicles, epidermis, hair follicles, sweat glands, corneal epithelium, proximal renal tubules, and epithelial linings of the gut and urinary tract. The CYP4F8 transcripts were detected by reverse transcription polymerase chain reaction and by Northern blot analysis. There was a prominent induction of CYP4F8 immunoreactivity and mRNA in psoriasis in comparison with unaffected epidermis of the same patients. The cDNA of CYP4F8 from plucked scalp hair roots was identical with the genital cDNA sequence. We conclude that CYP4F8 is present in epithelial linings and up regulated in epidermis of psoriatic lesions.
|
|
| 23. |
|
|
| 24. |
|
|
| 25. |
- Zhao, Ming, 1966-, et al.
(author)
-
Vascular smooth muscle cell proliferation requires both p38 and BMK1 MAP kinases
- 2002
-
In: Archives of Biochemistry and Biophysics. - 0003-9861 .- 1096-0384. ; 400:2, s. 199-207
-
Journal article (peer-reviewed)abstract
- Vascular smooth muscle cell (VSMC) proliferation is a key event in the progression of atherosclerosis. Induction of both c-fos (through the transcription factor Elk-1) and c-jun, both immediate early genes, is important for the stimulation of VSMC proliferation and migration. It was earlier found that p38 mitogen-activated protein (MAP) kinase upregulates c-jun gene transcription through phosphorylation of two myocyte enhancer factor 2 (MEF2) family transcription factors, MEF2A and MEF2C, while big MAP kinase 1 (BMK1) may upregulate c-jun gene transcription through MEF2A, MEF2C, and also MEF2D. Here, we report that inhibition of BMK1 by a dominant negative form of MEK5 or pharmacologic inhibition of p38 by SB 203580 additively suppress serum-induced VSMC proliferation. This additive effect of p38 and BMK1 inhibition implies that these two kinases coordinately regulate MEF2 transcription factors. The exclusive activation of MEF2D by BMK1 appears required for this cooperative upregulation of c-jun in VSMC, and coactivation of p38 and BMK1 also has additive effects on the activation of a reporter gene linked to the c-jun promoter in our experimental system. Thus, coordinate activity of both the p38 and BMK1 pathways appears necessary for optimal transcription of c-jun and, pari pasu, VSMC proliferation. These results may have implications for the future design of pharmacologic agents for inhibition of VSMC growth.
|
|
| 26. |
- Almeida, Joao, et al.
(author)
-
Characterization of major enzymes and genes involved in flavonoid and proanthocyanidin biosynthesis during fruit development in strawberry (Fragaria x ananassa)
- 2007
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861. ; 465:1, s. 61-71
-
Journal article (peer-reviewed)abstract
- The biosynthesis of flavonoids and proanthocyanidins was studied in cultivated strawberry (Fragaria x ananassa) by combining biochemical and molecular approaches. Chemical analyses showed that ripe strawberries accumulate high amounts of pelargonidin-derived anthocyanins, and a larger pool of 3',4'-hydroxylated proanthocyanidins. Activities and properties of major recombinant enzymes were demonstrated by means of in vitro assays, with special emphasis on specificity for the biologically relevant 4'- and 3',4'-hydroxylated compounds. Only leucoanthocyanidin reductase showed a strict specificity for the 3',4'-hydroxylated leucocyanidin, while other enzymes accepted either hydroxylated substrate with different relative activity rates. The structure of late flavonoid pathway genes, leading to the synthesis of major compounds in ripe fruits, was elucidated. Complex developmental and spatial expression patterns were shown for phenylpropanoid and flavonoid genes in fruits throughout ripening as well as in leaves, petals and roots. Presented results elucidate key steps in the biosynthesis of strawberry flavonoid end products. (c) 2007 Elsevier Inc. All rights reserved.
|
|
| 27. |
- Bardales, José R., et al.
(author)
-
CK2-mediated phosphorylation of a type II regulatory subunit of cAMP-dependent protein kinase from the mollusk Mytilus galloprovincialis
- 2007
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861 .- 1096-0384. ; 461:1, s. 130-137
-
Journal article (peer-reviewed)abstract
- Two isoforms of regulatory (R) subunit of cAMP-dependent protein kinase (PKA), named R(myt1) and R(myt2), were identified so far in the sea mussel Mytilus galloprovincialis. Out of them, only R(myt2) was phosphorylated in vitro by casein kinase 2 (CK2) using GTP as phosphate donor. CK2 catalytic subunit (CK2alpha) itself was sufficient to phosphorylate R(myt2), but phosphorylation was enhanced by the presence of the regulatory subunit CK2beta. Even in the absence of CK2, R(myt2) was phosphorylated to a certain extent when it was incubated with GTP. This basal phosphorylation was partially abolished by the known inhibitors apigenin and emodin, which suggests the presence of a residual amount of endogenous CK2 in the preparation of purified R subunit. CK2-mediated phosphorylation significantly decreases the ability of R(myt2) to inhibit PKA catalytic (C) subunit activity in the absence of cAMP. On the other hand, the sequence of several peptides obtained from the tryptic digestion of R(myt2) showed that mussel protein contains the signature sequence common to all PKA family members, within the "phosphate binding cassette" (PBC) A and B. Moreover, the degree of identity between the sequences of peptides from R(myt2), as a whole, and those from type II R subunits was 68-75%, but the global identity percentage with type I R subunits was only about 30%, so that R(myt2) can be classified as a type II R subunit.
|
|
| 28. |
- Basile, Maria, et al.
(author)
-
Paralemmin interacts with D3 dopamine receptors : implications for membrane localization and cAMP signaling
- 2006
-
In: Archives of Biochemistry and Biophysics. - : Elsevier. - 0003-9861 .- 1096-0384. ; 446:1, s. 60-68
-
Journal article (peer-reviewed)abstract
- Paralemmin is a novel lipid-anchored protein, which is highly expressed in neuronal plasma membranes. In this study, we demonstrate that paralemmin specifically interacts with the third intracellular loop of the D3 dopamine receptor. Utilizing co-immunoprecipitation and glutathione-S-transferase (GST) pulldown strategies, we demonstrate that paralemmin interacts exclusively with D3, but not D2 or D4 dopamine receptors or β-adrenergic receptors. Immunocytochemistry demonstrated co-localization of paralemmin and D3 receptor in vivo in hippocampus and cerebellum and in vitro in glial and neuronal cultures. Deletion mutational analysis indicates that amino acids 154–230 of paralemmin strongly interacted with amino acids 211–227 and 281–330 of the third intracellular loop of D3 receptor. The consequences of these interactions were investigated by co-expression in HEK293 cells. Cell surface biotinylation experiments demonstrate that paralemmin decreased D3 receptor concentration at the plasma membrane. Consistent with this observation, paralemmin expression decreased dopamine-stimulated adenylate cyclase activity. However, paralemmin also decreased basal, isoproterenol and forskolin-stimulated adenylate cyclase activity, suggesting a more general cellular function for paralemmin. Taken together, paralemmin has been implicated as a potent modulator of cellular cAMP signaling within the brain.
|
|
| 29. |
|
|
| 30. |
- Berna, Nathalie, et al.
(author)
-
Cosolvent-induced adsorption and desorption of serum proteins on an amphiphilic mercaptomethylene pyridine-derivatized agarose gel
- 1996
-
In: Arch Biochem Biophys. - : Elsevier BV. - 0003-9861. ; 330:1, s. 188-192
-
Journal article (peer-reviewed)abstract
- We studied the effects of the following cosolvents on the adsorption and desorption of serum proteins from an amphiphilic mercaptomethylene pyridine-derivatized agarose gel: glucose, sucrose, polyethylene glycol (PEG), 2-methyl-2,4-pentanediol (MFD), sorbitol, pentaerythritol, glycerol, and Na2SO4. The water-structuring salt 0.4 M Na2SO4 was the most potent promoter of protein adsorption, followed by 5 M sorbitol and, to a lesser extent, 0.2 M PEG 1000 and 2.25 M MPD. The other cosolvents (4 M glucose, 1.5 M sucrose, 0.3 M pentaerythritol, and 7.6 M glycerol) were unable to promote protein adsorption to the gel. Attempts to modulate the salt-promotion effect of Na2SO4 with different cosolvents demonstrated the occurrence of synergistic effects for pentaerythritol, sorbitol, and glucose and antagonistic effects for the other cosolvents. Sorbitol and glycerol were found to be the most interesting co-solvents studied, as the first promoted protein adsorption, whereas the other disrupted protein interaction. As a consequence of these novel findings we propose sorbitol and glycerol, both well-known protein stabilizers, as possible alternatives to water-structuring salts during the adsorption phase and to deleterious organic solvents during the desorption phase on amphiphilic gels.
|
|
| 31. |
|
|
| 32. |
|
|
| 33. |
- Breimer, Michael, 1951
(author)
-
Tissue specificity of glycosphingolipids as expressed in pancreas and small intestine of blood group A and B human individuals.
- 1984
-
In: Archives of biochemistry and biophysics. - 0003-9861. ; 228:1, s. 71-85
-
Journal article (peer-reviewed)abstract
- A chemical investigation has been done on blood group active glycosphingolipids of both small intestine and pancreas from two individuals, one blood group A and one blood group B. Total non-acid glycolipid fractions were prepared and the major blood group fucolipids present were purified and structurally characterized by mass spectrometry, proton NMR spectroscopy, and degradation methods. The glycolipid structures identified were a blood group Leb hexaglycosylceramide, a B-hexaglycosylceramide with a type 1 (Gal beta 1 leads to 3GlcNAc) carbohydrate chain, A-hexaglycosylceramides with types 1 and 2 (Gal beta 1 leads to 4GlcNAc) carbohydrate chains, a B-heptaglycosylceramide with a type 1 carbohydrate chain, and A-heptaglycosylceramides with type 1 and 2 carbohydrate chains. In addition several minor glycolipids having more than seven sugar residues were detected by thin-layer chromatography. The small intestine and pancreas had some distinct differences in their expression of the major fucolipids. The small intestine contained only glycolipids based upon type 1 carbohydrate chain while the pancreas had both type 1 and type 2 structures. The intestines contained mainly difucosyl compounds while the pancreas tissues contained both mono- and difucosyl glycolipids. Monofucosylglycolipids based on both types 1 and 2 saccharides were present in one pancreas while the other one contained only monofucosylcomponents based on type 1 chain. The ceramides of the intestinal glycolipids were found to be more hydroxylated (trihydroxy long-chain base, hydroxy fatty acids) compared to the pancreas glycolipids (dihydroxy long-chain base, non-hydroxy fatty acids).
|
|
| 34. |
- Burén, Jonas, et al.
(author)
-
Insulin action and signalling in fat and muscle from dexamethasone-treated rats
- 2008
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861 .- 1096-0384. ; 474:1, s. 91-101
-
Journal article (peer-reviewed)abstract
- Glucocorticoids initiate whole body insulin resistance and the aim of the present study was to investigate effects of dexamethasone on protein expression and insulin signalling in muscle and fat tissue. Rats were injected with dexamethasone (1mg/kg/day, i.p.) or placebo for 11 days before insulin sensitivity was evaluated in vitro in soleus and epitrochlearis muscles and in isolated epididymal adipocytes. Dexamethasone treatment reduced insulin-stimulated glucose uptake and glycogen synthesis by 30-70% in epitrochlearis and soleus, and insulin-stimulated glucose uptake by approximately 40% in adipocytes. 8-bromo-cAMP-stimulated lipolysis was approximately 2-fold higher in adipocytes from dexamethasone-treated rats and insulin was less effective to inhibit cAMP-stimulated lipolysis. A main finding was that dexamethasone decreased expression of PKB and insulin-stimulated Ser(473) and Thr(308) phosphorylation in both muscles and adipocytes. Expression of GSK-3 was not influenced by dexamethasone treatment in muscles or adipocytes and insulin-stimulated GSK-3beta Ser(9) phosphorylation was reduced in muscles only. A novel finding was that glycogen synthase (GS) Ser(7) phosphorylation was higher in both muscles from dexamethasone-treated rats. GS expression decreased (by 50%) in adipocytes only. Basal and insulin-stimulated GS Ser(641) and GS Ser(645,649,653,657) phosphorylation was elevated in epitrochlearis and soleus muscles and GS fractional activity was reduced correspondingly. In conclusion, dexamethasone treatment (1) decreases PKB expression and insulin-stimulated phosphorylation in both muscles and adipocytes, and (2) increases GS phosphorylation (reduces GS fractional activity) in muscles and decreases GS expression in adipocytes. We suggest PKB and GS as major targets for dexamethasone-induced insulin resistance.
|
|
| 35. |
|
|
| 36. |
- Burnett, D, et al.
(author)
-
Synthesis and secretion of procathepsin B and cystatin C by human bronchial epithelial cells in vitro: modulation of cathepsin B activity by neutrophil elastase
- 1995
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861. ; 317:1, s. 305-310
-
Journal article (peer-reviewed)abstract
- Procathepsin B and cystatin C are found in human lung secretions. We investigated the capacity of human bronchial epithelial cells to synthesize and secrete these proteins. Immunoprecipitation of [35S]methionine-labeled proteins from cultured bronchial epithelial cell lysates, followed by denaturing gel electrophoresis and autoradiography, showed the presence of newly synthesized procathepsin B of M(r) 42,000; no mature form was detected. Cathepsin B in conditioned medium from epithelial cells was tagged with benzyloxycarbonyl-125I-tyrosyl-alanine-diazomethane before and after treatment of the medium with neutrophil elastase. Control medium again showed a predominant form of cathepsin B with a M(r) of 42,000, but upon treatment with neutrophil elastase this protein was converted to a M(r) of 38,000, similar to the active form previously found in lung secretions, and cathepsin B activity was generated. The medium also contained the cathepsin B inhibitor, cystatin C, but cystatins A, B, S, SN, SA, and kininogen were not detected. After removal of cystatin C from the medium, elastase was still required to activate procathepsin B. These results suggest that bronchial epithelial cells are a source of procathepsin B and cystatin C in lung secretions. Cleavage both of cystatin C and procathepsin B by neutrophil elastase is essential for the generation of cathepsin B activity in the medium.
|
|
| 37. |
- Buss, Joan L, et al.
(author)
-
Oxidative stress mediates toxicity of pyridoxal isonicotinoyl hydrazone analogs
- 2004
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861 .- 1096-0384. ; 421:1
-
Journal article (peer-reviewed)abstract
- Pyridoxal isonicotinoyl hydrazone (PIH) and many of its analogs are effective iron chelators in vivo and in vitro, and are of interest for the treatment of secondary iron overload. Because previous work has implicated the Fe3+-chelator complexes as a determinant of toxicity, the role of iron-based oxidative stress in the toxicity of PIH analogs was assessed. The Fe3+ complexes of PIH analogs were reduced by K562 cells and the physiological reductant, ascorbate. Depletion of the antioxidant, glutathione, sensitized Jurkat T lymphocytes to the toxicity of PIH analogs and their Fe 3+ complexes, and toxicity of the chelators increased with oxygen tension. Fe3+ complexes of pyridoxal benzoyl hydrazone (PBH) and salicyloyl isonicotinoyl hydrazone (SIH) caused lipid peroxidation and toxicity in K562 cells loaded with eicosapentenoic acid (EPA), a readily oxidized fatty acid, whereas Fe(PIH)2 did not. The lipophilic antioxidant, vitamin E, completely prevented both the toxicity and lipid peroxidation caused by Fe(PBH)2 in EPA-loaded cells, indicating a causal relationship between oxidative stress and toxicity. PBH also caused concomitant lipid peroxidation and toxicity in EPA-loaded cells, both of which were reversed as its concentration increased. In contrast, PIH was inactive, while SIH was equally toxic toward control and EPA-loaded cells, without causing lipid peroxidation, indicating a much smaller contribution of oxidative stress to the mechanism of toxicity of these analogs. In summary, PIH analogs and their Fe3+ complexes are redox active in the intracellular environment. The contribution of oxidative stress to the overall mechanism of toxicity varies across the series. © 2003 Elsevier Inc. All rights reserved.
|
|
| 38. |
- Carvalho, Alexandra T. P., et al.
(author)
-
Modeling the mechanisms of biological GTP hydrolysis
- 2015
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861 .- 1096-0384. ; 582:SI, s. 80-90
-
Research review (peer-reviewed)abstract
- Enzymes that hydrolyze GTP are currently in the spotlight, due to their molecular switch mechanism that controls many cellular processes. One of the best-known classes of these enzymes are small GTPases such as members of the Ras superfamily, which catalyze the hydrolysis of the gamma-phosphate bond in GTP. In addition, the availability of an increasing number of crystal structures of translational GTPases such as EF-Tu and EF-G have made it possible to probe the molecular details of GTP hydrolysis on the ribosome. However, despite a wealth of biochemical, structural and computational data, the way in which GTP hydrolysis is activated and regulated is still a controversial topic and well-designed simulations can play an important role in resolving and rationalizing the experimental data. In this review, we discuss the contributions of computational biology to our understanding of GTP hydrolysis on the ribosome and in small GTPases.
|
|
| 39. |
- Chen, Mingzhi, et al.
(author)
-
Predicting protein folding cores by empirical potential functions
- 2009
-
In: Archives of Biochemistry and Biophysics. - New York : Elsevier. - 0003-9861 .- 1096-0384. ; 483:1, s. 16-22
-
Journal article (peer-reviewed)abstract
- Theoretical and in vitro experiments suggest that protein-folding cores form early in the process of folding, and that proteins may have evolved to optimize both folding speed and native-state stability. In our previous work (Chen et al., Structure, 14, 1401 (2006)), we developed a set of empirical potential functions and used them to analyze interaction energies among secondary-structure elements in two β-sandwich proteins. Our work on this group of proteins demonstrated that the predicted folding core also harbors residues that form native-like interactions early in the folding reaction. In the current work, we have tested our empirical potential functions on structurally-different proteins for which the folding cores have been revealed by protein hydrogen-deuterium exchange experiments. Using a set of 29 unrelated proteins, which have been extensively studied in the literature, we demonstrate that the average prediction result from our method is significantly better than predictions based on other computational methods. Our study is an important step towards the ultimate goal of understanding the correlation between folding cores and native structures.
|
|
| 40. |
- Chen, Yang, et al.
(author)
-
Purification and site-directed mutagenesis of linoleate 9S-dioxygenase-allene oxide synthase of Fusarium oxysporum confirms the oxygenation mechanism
- 2017
-
In: Archives of Biochemistry and Biophysics. - : ELSEVIER SCIENCE INC. - 0003-9861 .- 1096-0384. ; 625-626, s. 24-29
-
Journal article (peer-reviewed)abstract
- Plants and fungi form jasmonic acid from a-linolenic acid. The first two steps of biosynthesis in plants occur by sequential transformation by 13S-Iipoxygenase and allene oxide synthase (AOS). The biosynthesis in fungi may follow this classical scheme, but the only fungal AOS discovered so far are cytochromes P450 (CYP) fused to 8- and 9-dioxygenases (DOX). In the present report, we purified recombinant 9S-DOX-AOS of Fusarium oxysporum from cell lysate by cobalt affinity chromatography to near homogeneity and studied key residues by site-directed mutagenesis. Sequence homology with 8R-DOX-linoleate diol synthases (8R-DOX-LDS) suggested that Tyr414 catalyzes hydrogen abstraction and that Cys1051 forms the heme thiolate ligand. Site-directed mutagenesis (Tyr414Phe; Cys1051Ser) led to loss of 9S-DOX and 9S-AOS activities, respectively, but other important residues in the CYP parts of 5,8 and 7,8-LDS or 9R-AOS were not conserved. The UV-visible spectrum of 9S-DOX-AOS showed a Soret band at 409 nm, which shifted to 413 nm in the Cys1051Ser mutant. The 9S-AOS of the Tyr414Phe mutant transformed 9S-hydroperoxides of alpha-linolenic and linoleic acids to allene oxides/alpha-ketols, but it did not transform 13-hydroperoxides. We conclude that 9S- and 8R-DOX catalyze hydrogen abstraction at C-11 and C-8, respectively, by homologous Tyr residues.
|
|
| 41. |
|
|
| 42. |
- Christakopoulos, Paul, et al.
(author)
-
Purification and characterization of a less randomly acting endo-1,4-beta-D-glucanase from the culture filtrates of Fusarium oxysporum
- 1995
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861 .- 1096-0384. ; 316:1, s. 428-433
-
Journal article (peer-reviewed)abstract
- An extracellular endo-1,4-β-D-glucanase from Fusarium oxysporum was purified by affinity chromatography and gel filtration. The enzyme purified in this way was homogeneous when judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing-polyacrylamide gel electrophoresis. The protein corresponded to a molecular mass and pI value of 41.7 kDa and 6.4, respectively. It was optimally active at pH 4.5 and at 55°C. The enzyme hydrolyzed carboxymethylcellulose (CMC) and unsubstituted and substituted cello-oligosaccharides but was inactive on Avicel, filter paper, xylan, cellobiose, p-nitrophenyl-β-D-glucoside, and p-nitrophenyl-β-D-xyloside. However, the enzyme effected only a small change in viscosity of CMC per unit increase of reducing sugar. When cellotriose, cellotetraose, and cellopentaose were used as substrates, the enzyme released mainly cellobiose. Use of 4-methylumbelliferyl cello-oligosaccharides and the determination of bond cleavage frequency revealed that the enzyme preferentially hydrolyzed the glycosidic bond adjacent to 4-methylumbelliferone. Thus, the purified enzyme appeared to be a less randomly acting endoglucanase.
|
|
| 43. |
- Christakopoulos, Paul, et al.
(author)
-
Purification and mode of action of an alkali-resistant endo-1,4-β-glucanase from Bacillus pumilus
- 1999
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861 .- 1096-0384. ; 364:1, s. 61-66
-
Journal article (peer-reviewed)abstract
- Alkaline endo-1,4-β-d-glucanase was secreted byBacillus pumilusgrown in submerged culture on a combination of oat spelt xylan and corn starch as carbon sources. The enzyme was purified to homogeneity by Sephacryl S-200 and Q-Sepharose column chromatography. The protein corresponded to molecular mass and pIvalues of 67 kDa and 3.7, respectively. The enzyme was optimally active at pH 7.0–8.0 and 60°C and retained 50% of its optimum activity at pH 12. The most notable characteristic of the endoglucanase was its high stability up to pH 12 for 20 h at 30°C. The enzyme hydrolyzed carboxymethylcellulose (CMC) and cello-oligosaccharides but was inactive on cellobiose, cellotriose, Avicel, xylan, 4-nitrophenyl-β-d-glucoside, 4-nitrophenyl-β-d-cellobioside, and 4-nitrophenyl-β-d-xyloside. Analysis of reaction mixtures by HPLC revealed that the enzyme produced almost exclusively cellotriose when acted on CMC and appeared to hydrolyze cello-oligosaccharides by successively releasing cellotriose. The use of 4-methylumbelliferyl cello-oligosaccharides and the determination of bond cleavage frequency revealed that the enzyme preferentially hydrolyzed the third glycosidic bond adjacent to the glycon. The enzyme mediated a decrease in the viscosity of CMC associated with a release of only small amounts of reducing sugar. The enzyme activity was not inhibited by metal ions, surfactants, and chelating agents used as components of laundry detergents.
|
|
| 44. |
- Cisneros, David A., et al.
(author)
-
Inversion of the allosteric response of Escherichia coli glucosamine-6-P deaminase to N-acetylglucosamine 6-P, by single amino acid replacements
- 2004
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861 .- 1096-0384. ; 421:1, s. 77-84
-
Journal article (peer-reviewed)abstract
- Amino acid replacements in the active site of glucosamine-6-P deaminase from Escherichia coli (GlcN6P deaminase, EC 3.5.99.6) involving the residues D141 and E148 produce atypical allosteric kinetics. These residues are located in the chain segment 139-156 which is part of the active site and which also forms several intersubunit contacts close to the allosteric site. In the D141N and E148Q mutant forms of this deaminase, there is an inversion of the effect of its physiological allosteric effector, N-acetylglucosamine 6-P, which becomes an inhibitor at substrate concentrations above a critical value. For both mutants, this particular point appears at low substrate concentration and the inhibition by the allosteric activator is the dominant effect in velocity versus substrate curves. These effects are analyzed as a particular case of the concerted allosteric model, assuming that the R state, the conformer displaying the higher affinity for the substrate, is the less catalytic state, thus producing an inverted allosteric response.
|
|
| 45. |
- Coelho, Paulo G., et al.
(author)
-
Osseointegration of metallic devices : Current trends based on implant hardware design
- 2014
-
In: Archives of Biochemistry and Biophysics. - : Elsevier. - 0003-9861 .- 1096-0384. ; 561, s. 99-108
-
Research review (peer-reviewed)abstract
- Osseointegration of metallic devices has been one of the most successful treatments in rehabilitative dentistry and medicine over the past five decades. While highly successful, the quest for designing surgical instrumentation and associated implantable devices that hastens osseointegration has been perpetual and has often been approached as single variable preclinical investigations. The present manuscript presents how the interplay between surgical instrumentation and device macrogeometry not only plays a key role on both early and delayed stages of osseointegration, but may also be key in how efficient smaller length scale designing (at the micrometer and nanometer scale levels) may be in hastening early stages of osseointegration. (C) 2014 Elsevier Inc. All rights reserved.
|
|
| 46. |
|
|
| 47. |
|
|
| 48. |
|
|
| 49. |
- Cristea, Mirela, et al.
(author)
-
Expression of manganese lipoxygenase in Pichia pastoris and site-directed mutagenesis of putative manganese ligands
- 2005
-
In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861 .- 1096-0384. ; 434:1, s. 201-211
-
Journal article (peer-reviewed)abstract
- Manganese lipoxygenase is secreted by the fungus Gaeumannomyces graminis. We expressed the enzyme in Pichia pastoris, which secreted approximately 30 mg Mn-lipoxygenase/L culture medium in fermentor. The recombinant lipoxygenase was N- and O-glycosylated (80-100 kDa), contained approximately 1 mol Mn/mol protein, and had similar kinetic properties (K(m) approximately 7.1 microM alpha-linolenic acid and V(max) 18 nmol/min/microg) as the native Mn-lipoxygenase. Mn-lipoxygenase could be quantitatively converted, presumably by secreted Pichia proteases, to a smaller protein (approximately 67 kDa) with retention of lipoxygenase activity (K(m) approximately 6.4 microM alpha-linolenic acid and V(max) approximately 12 nmol/min/microg). Putative manganese ligands were investigated by site-directed mutagenesis. The iron ligands of soybean lipoxygenase-1 are two His residues in the sequence HWLNTH, one His residue and a distant Asn residue in the sequence HAAVNFGQ, and the C-terminal Ile residue. The homologous sequences of Mn-lipoxygenase are H274VLFH278 and H462HVMN466QGS, respectively, and the C-terminal amino acid is Val-602. The His274Gln, His278Glu, His462Glu, and the Val-602 deletion mutants of Mn-lipoxygenase were inactive, and had lost >95% of the manganese content. His-463, Asn-466, and Gln-467 did not appear to be critical for Mn-lipoxygenase activity, as His463Gln, Asn466Gln, Asn466Leu, and Gln467Asn mutants metabolized alpha-linolenic acid to 11- and 13-hydroperoxylinolenic acids. We conclude that His-274, His-278, His-462, and Val-602 likely coordinate manganese.
|
|
| 50. |
|
|
