Denaturation of plant proteins. IV. Increase in reducing capacity, viscosity, and optical rotation upon denaturation with guanidine hydrochloride

Abstract

AbstractLegumin of vetch and tuberin of potato have been denatured by guanidine hydrochloride. It was found that the reducing capacity (as estimated by titration with iodine in slightly acid solutions), the optical rotation, and the viscosity thereby increase. The specific rotation of legumin is increased from −42° for native legumin up to −90° for denatured legumin. The optical rotation and reducing capacity decrease with decreasing pH. According to the titration data, only about 12% of the sulfide can be detected by iodine; upon denaturation, the amount of detectable SH groups increases up to 40–80%.