Glutathione reductase kinetics

Reaction Mechanism and Kinetic Constants for a Reaction Catalyzed by Glutathione Reductase... 

The early kinetic studies on glutathione reductase did not include investigation of product inhibition, so vital to a proper interpretation of kinetic data in the elucidation of the mechanism 247, 248). In the one case where product inhibition patterns were observed, they were not interpreted by more recent kinetic theory 40). Subsequent kinetic analyses see below), in which product inhibition patterns have been obtained, were either completed prior to the discovery of the EH2-NADPH complex... 

Kinetic parameters are given in Table VI. Plots of 1/v against 1/(S) ve parallel lines both at 4° and 25° on this basis the assumption has been made that a binary complex mechanism is operative. As with lipo-amide dehydrogenase and glutathione reductase, this assumption is com-... 

Glutathione reductase amino acid composition, 102,104,105 cystine residues, 104 kinetic studies, 138-141 mechanism, 94, 97-98,134 metabolic functions, 129-133 reaction catalyzed, 92 reduction of, 112, 113 specificity of, 92-93 coenzymes and, 94 thiol groups, 141-142 two-electron-reduced enzyme, properties, 133-138... 

Ramos-Martinez JI, Torres AMR (1985b) Glutathione reductase of mantle tissue from sea mussel Mytilus edulis L. — II. Kinetic mechanism and regulation of two seasonal forms. Comp Biochem Physiol 80B 917-921... 

Vanoni, M. A., Wong, K. K., Ballon, D. P. Blanchard, J. S. (1990). Glutathione reductase comparison of steady-state and rapid reaction primary kinetic isotope effects exhibited by the yeast, spinach and coli enzymes. Biochemistry, 29,5790-96. 

The reduction of retinaldehyde to retinol was studied with an approximately 13-fold purified soluble enzyme preparation from rat intestinal mucosa (Fidge and Goodman, 1968). The enzyme was relatively heat stable and had a molecular weight approximately in the range of 60,000-80,000. The partly purified reductase was unable to oxidize ethanol in the presence of NAD" ". Retinaldehyde reduction required NADH or NADPH as cofactor both reduced nucleotides were effective. The reaction was stimulated by glutathione and inhibited by thiol inhibitors. There was a sharp pH optimum near 6.3. Retinaldehyde reduction displayed typical Michaelis kinetics, with a 2 xmol of retinol formed per... 

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