Glutathione reductase

Glutathione reductase (EC 1.8.1.7) is a ubiquitous homodimeric enzyme with molecular weights ranging from 100 kDa, for the human erythrocyte enzyme, to 118 kDa, for the yeast enzyme. It contains one FAD per protein subunit and shows Km values of 4-9 µM for NADPH and of 55-65 µM for oxidized glutathione. The GR is inhibited by divalent metal ions, such as Zn²⁺ and Cd²⁺, which can be prevented by the addition of EDTA. The enzyme is also inhibited by ammonium sulphate (>60 mM) but not by urea (0.6 M), Triton X-100 (1%) and KCl (100 mM). The biochemical function of flavoprotein glutathione reductase is to catalyse the NADPH-dependent reduction of oxidized glutathione. The glutathione is a tripeptid widely distributed in both plants and animals. Thus, the enzyme is found in many tissues, enabling the cells to maintain adequate levels of reduced glutathione. Reduced glutathione is an important cellular antioxidant and is also a substrate for the glutathione peroxidases, which provide a mechanism for the detoxification of xenobiotics. The enzyme is provided in 3.2 M ammonium sulphate.

Activity: 98 U/ml

Temperature and pH optimum/stability: The optimum pH and temperature are 7.5 and 25 °C, respectively.