Fc fragment of human immunoglobulin G: Reduction and carboxymethylation of inter-chain disulfide bonds enhances complement activating capacity

Abstract

The complement activating capacity of the Fc fragment of human immunoglobulin G increases after selective reduction and carboxymethylation of the inter-chain disulfide bonds. Differences in the circular dichroism spectra of intact and modified fragment suggest that minor conformational changes have occurred. Our results are discussed in relation to the molecular requirements for complement activation.