Amperometric Titration of -SH Groups in Purified Clotting Factors By Improved Method

Abstract

The ethanol-ammoniacal amperometric method for quantitative measurement of -SH groups in proteins is susceptible to valid criticism. Previous work, employing this method, resulted in the inability to detect -SH groups in purified bovine prothrombin or its derivatives. Titration of these proteins by the new method described by Benesch, Lardy and Benesch, employing tris- (hydroxy-methylaminomethane) in aqueous, buffered solutions at pH 7.4, also resulted in the inability to detect -SH groups in these proteins.