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- Florén, Claes-Henrik, et al.
(författare)
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Effects of fatty acid unsaturation on chylomicron metabolism in normal and hepatectomized rats
- 1977
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Ingår i: Eur J Biochem. - : Wiley. - 0014-2956. ; 77:1, s. 23-30
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Tidskriftsartikel (refereegranskat)abstract
- 1. Hepatectomized rats were injected intravenously with doubly labelled ([14C]linoleic acid and [3H]palmitic acid) thoracic duct lymphs from rats fed cream, triolein or corn oil. The disappearance of the radioactive fatty acids of different molecular triacylglycerol species and of phospholipids from plasma was studied.2. 73–93% of the injected triacylglycerols had been cleared from plasma within 15 min. At all stages of lipolysis the 3H/14C ratio of the plasma triacylglycerol was the same as in the injected material. If the cream chyle had been cooled to 4 °C before use there was, however, an enrichment of [3H]palmitic acid and of fully saturated triacylglycerols in the remnant particles formed.3. Only 38–50% of the radioactive chyle phosphatidylcholine was eliminated from plasma in 30 min. At this time most of the remaining phosphatidylcholine was, however, in other lipo‐protein classes than the chylomicron remnants.4. Also in intact rats data were obtained, indicating that the major portion of chylomicron phospholipids is transferred to other serum lipoproteins by exchange or net movement rather than being hydrolysed in the 1‐position by lipoprotein lipase or taken up intact by the liver.5. More of both the labelled fatty acids appeared in liver triacylglycerols in experiments with cream chyle than in experiments with corn oil chyle. Data were obtained suggesting that this may be due to a higher uptake of intact triacylglycerol as remnant particles.6. When linoleic acid is fed as a tracer dose in cream, a high proportion (16–36%) is incorporated into chyle phospholipids.
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| 6. |
- Höjeberg, B, et al.
(författare)
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Affinity Chromatography and Binding Studies on Immobilized Adenosine 5'-Monophosphate and Adenosine 2'.5'-Bisphosphate of Nicotinamide Nucleotide Transhydrogenase from Pseudomonas aeruginosa
- 1976
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Ingår i: European Journal of Biochemistry. - : Wiley. - 0014-2956 .- 1432-1033. ; 66:3, s. 467-475
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Tidskriftsartikel (refereegranskat)abstract
- Nicotinamide nucleotide transhydrogenase from Pseudomonas aeruginosa was purified to apparent homogeneity with an improved method employing affinity chromatography on N6-(6-aminoyl)-adenosine-2′,5′-bisphosphate-Sepharose 4B. Polyacrylamide gel electrophoresis of the purified transhydrogenase carried out in the presence of sodium dodecyl sulphate, indicated a minimal molecular weight of 55000 ± 2000. The kinetic and regulatory properties of the purified transhydrogenase resembled those of the crude enzyme, i.e., NADPH, adenosine 2′-monophosphate and Ca2+were activators whereas NADP+was inhibitory. Nicotinamide nucleotide-specific release of binding of the transhydrogenase to N6-(6-aminohexyl)-adenosine-2′,5′-bisphosphate-Sepharose and N6-(6-aminohexyl)-adenosine-5′-monophospliate-Sepharose suggests the presence of at least two separate binding sites for nicotinamide nucleotides, one that is specific for NADP(H) and one that binds both NAD(H) and NADP(H). Binding of transhydrogenase to N6-(6-aminohexyl)-adenosine-2′,5′-bisphosphate-Sepharose and activation of the enzyme by adenosine-2′,5′-bisphosphate showed a marked pH dependence. In contrast, inhibition of the Ca2+-activated enzyme by adenosine 2′,5′-bisphosphate was virtually constant at various pH values. This discrepancy was interpreted to indicate the existence of separate nucleotide-binding effector and active sites.
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| 8. |
- Brodelius, Peter, et al.
(författare)
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The Synthesis of Three AMP-Analogues: N6-(6-Amino-hexyl)-Adenosine 5'-Monophosphate, N6-(6-Aminohexyl)-Adenosine 2',5'-Bisphosphate, and N6-(6-Aminohexyl)-Adenosine 3',5'-Bisphosphate and Their Application as General Ligands in Biospecific Affinity Chromatography
- 1974
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Ingår i: European Journal of Biochemistry. - 0014-2956 .- 1432-1033. ; 47, s. 81-89
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Tidskriftsartikel (refereegranskat)abstract
- Phosphorylation of 6-chloropurine riboside with phosphorus oxychloride and phosphorus trichloride gave a mixture of the two isomers, 6-chloropurine-riboside 2’,5‘-bisphosphate and 6-chloropurine-riboside 3‘,5‘-bisphosphate. Reaction with Iy6-diaminohexane followed by resolution of the isomeric mixture on a Dowex 1-X2 column yielded N6-(6-aminohexyl)-adenosine 2’,5’-bisphosphate and N6-(6-aminohexyl)-adenosine 3’,5‘-bisphosphate.The inhibition of several NADP+-dependent and NAD+-dependent dehydrogenases by N6-(6-aminohexyl)-adenosine 2’,5‘-bisphosphate, N6-(6-aminohexyl)-adenosine 3’,5’-bisphosphate and N6-(6-aminohexyl)-adenosine 5’-monophosphate was examined.These three AMP-analogues were attached to Sepharose 4B by the cyanogen bromide method and the binding of several NAD(P)+-dependent enzymes were investigated. NADP+-dependent enzymes were bound to Sepharose substituted with N6-(6-aminohexyl)-adenosine 2’,5‘-bisphosphate, whereas NAD+-dependent enzymes were not bound under the same conditions. Conversely, when N6-(6-aminohexy1)-adenosine 5‘-monophosphate was used as the immobilised ligand only the NAD+- dependent enzymes were bound, as well as glucose-6-phosphate dehydrogenase showing weak affinity. These observations strongly suggest that these two immobilised analogues represent true biospecific and group-specific adsorbents. The enzymes were eluted with their complementary nucleotides, NAD(H) and NADP(H). These techniques were utilised to purify several NADPf-dependent enzymes from a crude Candida utilis extract by chromatography on the new biospecific adsorbent.
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| 9. |
- Chester, Alan, et al.
(författare)
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Biosynthesis of the blood-group-B-specific trisaccharide in a rhesus monkey
- 1977
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Ingår i: European Journal of Biochemistry. - 0014-2956. ; 77:1, s. 87-91
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Tidskriftsartikel (refereegranskat)abstract
- A Rhesus monkey, serologically grouped as B, has been shown to excrete low-molecular-weight carbohydrate material in urine closely related to that found in human urine. Galactose feeding resulted in the excretion of a trisaccharide which was shown to be identical to the trisaccharide isolated from the urine of group B humans under the same conditions. Experiments in which [14C]galactose was administered both orally and via an intestinal vein demonstrated that the intestine is the site of biosynthesis.
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| 10. |
- Chester, Alan, et al.
(författare)
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Phenyl beta-D-Galactopyranoside as an Acceptor Substrate for the Blood-Group H Gene-Associated Guanosine Diphosphate L-Fucose:beta-D-Galactosyl alpha-2-L-Fucosyltransferase
- 1976
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Ingår i: European Journal of Biochemistry. - 0014-2956. ; 69:2, s. 583-592
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Tidskriftsartikel (refereegranskat)abstract
- Phenyl β-d-galactopyranoside was found to be an efficient acceptor of l-[14C]fucose when guanosine diphosphate l-[14C]fucose was used as the donor substrate and human serum, submaxillary glands or stomach mucosa were the sources of l-fucosyltransferase. The enzyme utilising phenyl β-D-galactoside was present in the serum of donors of all ABO blood-groups examined, except those of the rare Oh (Bombay) and Bh phenotypes, but was clearly demonstrable in submaxillary gland preparations only when the glands came from individuals who were secretors of ABH blood-group substances. This distribution coincides with that previously established for the blood-group H gene-specified α-2-l-fucosyltransferase. The product of l-[14C]fucosyl transfer to phenyl β-d-galactoside is separable from the other radioactive components in the enzyme digest by chromatography for 4 h in ethyl acetate/pyridine/water (10/4/3, by vol.); it was characterised as phenyl 2-O-(α-l-[14C]fucopyranosyl)β-d-galactopyranoside by (a) the liberation of l-[14C]fucose by a specific α-2-l-fucosidase, (b) its resistance to degradation by alkali and (c) the identification of tritiated glycerol as a product of periodate oxidation after a 3H label had been introduced into the galactosyl moiety. The use of phenyl β-d-galactopyranoside as acceptor substrate thus provides a simple and relatively rapid method for the assay of the blood-group H gene-specified α-2-l-fucosyltransferase.
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