Glutathione reductase of mantle tissue from sea mussel Mytilus edulis L—I. Purification and characterization of two seasonal enzymatic forms

Abstract

1. 1. Glutathione reductase (GSSG-R) from mantle tissue of Mytilus edulis exists in two forms (I and II). GSSG-R I is present throughout the year and in the present study was purified 92-fold by extraction, ammonium sulphate fractionation, ion-exchange chromatography on DEAE-Sephadex, absorption chromagraphy on hydroxyapatite and gel-filtration on Sephadex G-200. 2. 2. GSSG-R II is only present in winter, and in the present study was purified 115-fold by a process similar to that used to purify GSSG-R I. Unlike GSSG-R I, the winter form GSSG-R II is not retained by DEAE-Sephadex. 3. 3. GSSG-R I and GSSG-R II give different gel electrophoresis patterns and have different mol. wts (90,000 and 70,000 daltons respectively). 4. 4. GSSG-R I is activated by pre-incubation at 25, 35 or 45°C, and GSSG-R II inactivated. 5. 5. Both forms are adapted to in vivo salt conens, but GSSG-R I is more sensitive to changes than GSSG-R II. 6. 6. GSSG-R I is inactivated by NADPH and GSH and slightly activated by NADP +. GSSG-R II is not observed to be either inactivated by NADPH or activated by NADP +, but like the other form is inactivated by GSH.