Disulfide bonds: determination, location, and influence on molecular properties of proteins.

Determination and location of cystine residues are essential to protein characterization since their disulfide bonds stabilize chainfolding and multichain structure responsible for physical and biological properties. Reduction with mercaptans, such as dithiothreitol, in dissociating solvents is the choice procedure for attaining disulfide cleavage, since other methods may cause undesirable side reactions. Under selected conditions the resulting sulfhydryls can be specifically alI..')'lated with a"S-unsaturated compounds to prevent their reoxidation. Determination of alkylated cysteine residues supplements