[Glutathatione-dehydrogenase of wheat flour. Purification and properties (author's transl)].

Glutathione: dehydroascorbic acid oxidoreductase (EC 1.8.5.1) has been purified to essential homogeneity by precipitation with (NH4)2SO4, and ion-exchange chromatography on CM-Sephadex and DEAE-cellulose. The molecular weight is 24200 Dalton as determined by SDS-PAG-electrophoresis. The amino acid composition was analysed. The esed. The enzyme ist specific for glutathione as H-donor and it reduces the L-threo-diasteromer faster than the L-erythro- and D-erythro-dehydroascorbic acid. The enzyme is inhibited by iode acetic acid and N-ethyl-maleinimide. Zero-order kinetics was only observed for the hydrogen-acceptor but not for glutathione.