An essential role of cytosolic thioltransferase in protection of pyruvate kinase from rabbit liver against oxidative inactivation.

Pyruvate kinase from rabbit liver is inactivated spontaneously in the presence of air. Glutathione in physiological concentrations gives partial protection against inactivation. Full protection is obtained with glutathione and purified cytosolic thioltransferase supplemented with a glutathione-regenerating system. It is suggested that thioltransferase plus glutathione serve a general function in protecting protein thiol groups against oxidation.