DT-diaphorase catalyzes N-denitration and redox cycling of tetryl.
Rat liver DT-diaphorase (EC 1.6.99.2) catalyzed reductive N-denitration of tetryl (2,4,6-tri-nitrophenyl-N-methylnitramine) and 2,4-dinitrophenyl-N-methylnitramine, oxidizing the excess of NADPH. The reactions were accompanied by oxygen consumption and superoxide dismutase-sensitive reduction of added cytochrome c and reductive release of Fe2+ from ferritin. Quantitatively, the reactions of DT-diaphorase proceeded like single-electron reductive N-denitration of tetryl by ferredoxin:NADP+ reductase (EC 1.18.1.2) (Shah, M.M. and Spain, J.C. (1996) Biochem. Biophys. Res. Commun. 220, 563-568), which was additionally checked up in this work. Thus, although reductive N-denitration of nitrophenyl-N-nitramines is a net two-electron (hydride) transfer process, DT-diaphorase catalyzed the reaction in a single-electron way. These data point out the possibility of single-electron transfer steps during obligatory two-electron (hydride) reduction of quinones and nitroaromatics by DT-diaphorase.
Institute of Biochemistry, Vilnius, Lithuania.
Z
Z
Anusevicius
J
J
Sarlauskas
H
H
Nivinskas
J
J
Segura-Aguilar
N
N
Cenas
D000814:Aniline Compounds / Q000493:pharmacokinetics*; D000818:Animals; D001711:Biotransformation; D008058:Dihydrolipoamide Dehydrogenase / Q000378:metabolism*; D004136:Dinitrobenzenes / Q000493:pharmacokinetics; D005287:Ferredoxin-NADP Reductase / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D009249:NADP / Q000378:metabolism; D009578:Nitrobenzenes / Q000493:pharmacokinetics*; D010084:Oxidation-Reduction; D051381:Rats; D013053:Spectrophotometry
C115215:2,4-dinitrophenyl-N-methylnitramine; D000814:Aniline Compounds; D004136:Dinitrobenzenes; D009578:Nitrobenzenes; D009249:NADP; D005287:Ferredoxin-NADP Reductase; D008058:Dihydrolipoamide Dehydrogenase; C015384:nitramine