Complex-formation between polypeptides and metals. 1. Application of various experimental methods to the glycine–copper system

Abstract

follow the reaction of GSSG and cystine with silver nitrate. Since GSSG and GSH were both subject to the same error the interpretation of this reaction is unaffected. The cystine concentrations on the other hand were correct, whereas the cysteine figures were 17 % high. This reaction is therefore slower than it appeared and the difference in reactivity between the two substances greater. Details will not be given here, as work on these and other com- pounds is continuing. SUMMARY 1. A method for the estimation of four thiols bv potentiometric titration with silver nitrate is described. The titrations are carried out in buffered solutions, the pH used depending on the particular compound. In all cases one of two pH ranges, 1-8-2-2 or 6-5-7-0, can be used.