title: Location of the inter-chain disulfide bonds of the third component of human complement.
abstract: Location of the disulfide bonds connecting three polypeptide chains (alpha 3, 27kd; 2, 43kd; beta, 75kd) of C3c has been investigated by partial reduction with cysteine followed by alkylation with 14C-monoiodoacetic acid. Treatment of C3c with cysteine produced a partially reduced fragment, composed of disulfide-linked beta and alpha 3 chains. A single thiol residue was detected on the alpha 3 chain but not on the beta chain of the fragment, suggesting that the alpha 2 chain in C3c is linked through a single disulfide bond to the alpha 3 chain but not to the beta chain.
mesh_terms: D003176:Complement C3 / Q000032:analysis*; D004220:Disulfides / Q000032:analysis*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D011487:Protein Conformation
chemical_list: D003176:Complement C3; D004220:Disulfides