Gamma-A cold agglutinin: importance of disulfide bonds in activity and structure.

Cleavage of disulfide bonds caused by mild reduction with mercaptoethanol produces a reversible loss of cold agglutinin activity and antigen-binding ability in a gamma-A polymer cold agglutinin. Return of agglutination and antigen-binding ability occur only in those molecules that have not been depolyimerized by reduction. Loss of activity becomes irreversible if reduction is followed immediately by alkylation.