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- Hober, Sophia, et al.
(författare)
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Disulfide exchange folding of insulin-like growth factor I.
- 1992
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 31:6
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Tidskriftsartikel (refereegranskat)abstract
- The disulfide exchange folding properties of insulin-like growth factor I (IGF-I) have been analyzed in a redox buffer containing reduced (10 mM) and oxidized (1 mM) glutathione. Under these conditions, the 3 disulfide bridges of the 70 amino acid peptide were not quantitatively formed. Instead, five major forms of IGF-I were detected, and these components were concluded to be in equilibrium as their relative amounts were similar starting from either reduced, native, or a mismatched variant of IGF-I containing two non-native disulfides. The different components in the mixtures were trapped by thiol alkylation using vinylpyridine and subsequently isolated by reverse-phase HPLC. The purified variants were further characterized using plasma desorption mass spectrometry and peptide mapping. Two of the five different forms were identified as native and mismatched IGF-I. One form was a variant with only one disulfide bond, and the other two major components had two disulfides formed. In a separate experiment, early refolding intermediates were trapped by pyridylethylation after only 90 s of refolding in the glutathione buffer, starting from reduced IGF-I. The intermediates were identical to the components observed at equilibrium, but at different relative concentrations. On the basis of the disulfide bond patterns of the different components in the equilibrium mixtures, we conclude that the disulfide between cysteines-47 and -52 in IGF-I is an unfavorable high-energy bond that may exist in the native molecule in a strained configuration.
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| 5. |
- Forsberg, S, et al.
(författare)
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The effect of contact time between cationic polymers and furnish on retention and drainage
- 1994
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Ingår i: Journal of Pulp and Paper Science (JPPS). - 0826-6220. ; 20, s. J71-J76
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Tidskriftsartikel (refereegranskat)abstract
- The effect of the contact time between cationic polymers (polyacrylamides and cationic starches) and stock on retention and dewatering has been studied using a new type of equipment. Dewatering is carried out under low pressure and the addition of chemicals and other operations are controlled by a microprocessor. The retention often shows a maximum after a polymer contact time of 10-20 s. It is found that long contact times drastically reduce the effect of the added polymer. This is explained as being due to floc rupture, degradation of the polymer and poor reflocculation. The dewatering time is extremely sensitive to the polymer contact time and increases steadily with increasing contact time.
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| 6. |
- Nilsson, B, et al.
(författare)
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Reconstitution of the alternative pathway of complement by plasma infusions given to a patient with an SLE-like syndrome associated with a hereditary C3 dysfunction.
- 1994
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Ingår i: Annals of the Rheumatic Diseases. - 0003-4967 .- 1468-2060. ; 53:10, s. 691-694
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To reconstitute a dysfunctional form of complement factor C3 in a patient with a systemic lupus erythematosus (SLE)-like syndrome.METHODS: The propositus was treated with plasma infusions during five sessions over a period of eight months.RESULTS: The alternative pathway was reconstituted to normal levels for approximately two to three days after each infusion. C3 fragments were incorporated into previously detected deposits of IgG and IgM at the dermal-epidermal junction and the immune complex levels gradually decreased during the whole treatment period.CONCLUSION: The reconstitution appears to result in the solubilisation of tissue immune complexes and a subsequent transportation to the fixed macrophage system.
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| 7. |
- Nilsson, U R, et al.
(författare)
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Hereditary dysfunction of the third component of complement associated with a systemic lupus erythematosus-like syndrome and meningococcal meningitis.
- 1992
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Ingår i: Arthritis and Rheumatism. - 0004-3591 .- 1529-0131. ; 35:5, s. 580-586
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: We describe a dysfunction of C3 in a patient with a systemic lupus erythematosus (SLE)-like syndrome. Alternative pathway complement function was absent, but classical pathway complement function was partially intact.METHODS: We used functional, preparative, and immunochemical techniques in the study.RESULTS: The patient's C3 proved normally susceptible to trypsin proteolysis and partially resistant to classical pathway, but completely resistant to alternative pathway, convertase-dependent cleavage.CONCLUSION: The dysfunction, thus, was caused by a failure of C3 to interact with the C3 convertases, rather than by a lack of a proteinase-sensitive cleavage site in the deficient protein.
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