Detection of disulphide bonds and localization of interchain linkages in the third (C3) and the fourth (C4) components of human complement

摘要: Disulphide bonds contribute significantly to the maintenance of structural/functional integrity many proteins. Therefore it was interest study distribution and effect disulphides on conformation complement components C3 C4. These proteins are precursors several fragments with various binding sites distinct physiological functions. The constituents C3c (beta, alpha 27, 43) those C4c 16, gamma) were investigated, since other or C4 do not participate in interchain linkages. Inter-and intra-chain disulphide localized by using a modification conventional SDS (sodium dodecyl sulphate)/polyacrylamide-gel electrophoresis such that change mobility disulphide-bond-containing can be detected throughout transition from non-reduced fully reduced state. Several forms 43 fragment C3, gamma-chain C4, different mobilities exist, depending number reduced. intermediates (heterodimers) generated partial reduction characterized two-dimensional SDS/polyacrylamide-gel performed absence, then presence, beta-mercaptoethanol. inter-chain linkages determined beta-alpha 27 27- 43, thus indicating presence only one bond C3. two 16-gamma. third (alpha 27-gamma, tentative) remains determined.