[Inactivation of glutathione reductase by quinones and nitrosocarbamides].
Quinones inactivate oxidized glutathione reductase (EC 1.6.4.2) from yeast with rate constants (ki) ranging from 0.03 M-1s-1 (p-benzoquinone) to 10(3) M-1s-1 (bromanyl). It is glutathione, but not NADP+ that protects the enzyme from inactivation, which shows that quinones interact with a glutathione-binding centre, cysteine-2, most probably. The mechanism of inactivation by quinones differs from that by nitrosoureas which inactivate only the reduced enzyme, modifying the reduced catalytic disulphide. 1,3-bis-(2-chloroethyl)-1-nitrosourea acts as the most rapid inactivator of the enzyme, possessing ki of 0.77 M-1s-1.
Bironaĭte
D A
DA
Chenas
N K
NK
Lutsenko
V V
VV
D001665:Binding Sites / Q000187:drug effects; D002384:Catalysis; D005980:Glutathione Reductase / Q000037:antagonists & inhibitors*; D007700:Kinetics; D015394:Molecular Structure; D009607:Nitrosourea Compounds / Q000494:pharmacology*; D010084:Oxidation-Reduction; D011809:Quinones / Q000494:pharmacology*; D012441:Saccharomyces cerevisiae / Q000201:enzymology
D009607:Nitrosourea Compounds; D011809:Quinones; D005980:Glutathione Reductase
Inaktivatsiia gliutationreduktazy khinonami i nitrozokarbamidami.