Purification and properties of glutathione reductase from hepatopancreas of Mytilus edulis L.

Abstract

1. 1. The enzyme glutathione reductase (GR) from hepatopancreas of Mytilus edulis L. was purified 80-fold by extraction, fractionated precipitation with ammonium sulphate, ion-exchange chromatography on DEAE-Sephadex, absorption chromatography on hydroxyapatite and gel-filtration through Sephadex G-200. 2. 2. The optimal pH was 7.5 and the K m for GSSG and NADPH were respectively 0.065 and 0.0041 mM. 3. 3. Glutathione reductase is rapidly activated by preincubation at 40°C either alone or with 1 mM GSSG. After 2 hr incubation the activity is 150% of the initial value. At 60°C the enzyme is rapidly inactivated, whether incubated alone or in the presence of 0.1 mM NADP +. One mM GSSG protects the activity of the enzyme to some extent. At 20°C glutathione reductase is inactivated by NADPH and GSH. 4. 4. NaCl and KCl at concentrations close to those they have in seawater are activators. Contrary to the findings of other authors zinc sulphate is also a strong activator of enzyme at 0.2 mM concentration.