Copper(II) induced polymerization of human albumin, and its depolymerization by diglycyl-L-histidine: A pH static and ultracentrifugation study
✍ Scribed by R. Österberg; B. Braneg»rd; R. Ligaarden; B. Sarkar
- Publisher
- Elsevier Science
- Year
- 1975
- Weight
- 977 KB
- Volume
- 5
- Category
- Article
- ISSN
- 0006-3061
No coin nor oath required. For personal study only.
✦ Synopsis
Copper(U) ions successively induce dimers and tetramers of human serum albumin (L) when the Cu(H) concentration is extended beyond that of 200 MM. This is shown by emf titrations and by ukracentrifugation experiments_
The emf titrations, which involve a new pH static method, were performed at 25", in a 0.5 hl NaClO, medium at pH 6.59, using glass and copper amalgam electrodes. The total concentration of Cu(I1) varied from 0.14 to 2.2 mM and the albumin concentration from 0.05 to 0.7 mM_ In order to evaluate the formula of the main complexes, without usin g any a priori assumptions regarding their compositions, a detailed graphic procedure was used. The results, in the form of equilibrium constants for the main species, were refmed by the use of a general least squares computer program. The experimental data are found to be consistent with the formation of the monomeric CuL, Cu, L, and Cu, L species and the dimeric Cu, L2, Cu, L, , Cu, L2, and Cu, L, species.
In addition, there is some indication for a minor species, most probably the Cu, z L, tetramer The pH static results qualitatively agree with the findings obtained by uhracentrifugation. As indicated by distinct bands and their