Abstract: Glutathione reductase (GR) is an enzyme that plays important physiological role and widely distributes throughout organisms.GR catalyzes reaction to turn the oxidized glutathione (GSSG) into the reduced glutathione (GSH).In this study,GR was purified to electrophoretically homogeneous state from earthworm Eisenia fetida. The purification process involved flash extraction,ultrasonic extraction,acetone precipitation,ammonium sulfate precipitation and ion exchange chromatography.The results showed that the optimal extraction conditions determined by orthogonal experiments were:pH of 7.5,solid/liquid ratio of 1:5,extraction time of 45 s,and ultrasonic treatment time of 15 min.Under these conditions,GR was purified 32.3-fold to a specific activity of 655.9 U/mg pr.,and was obtained with a yield of 58.4%.The molecular weight of the purified enzyme was estimated 110 kDa by SDS-PAGE.The optimal pH and temperature were 8.0 and 50 °C for GR.

Key words: earthworms, glutathione reductase, flash extraction, purification