[Oxidation of some substrates in the presence of NAD(P)-dependent oxidoreductases and 4-anilino-5-methoxybenzoquinone-1,2 with transfer of reducing equivalents to oxygen].

A reaction sequence for oxidation of L-lactate, ethanol, D-glucose-6-phosphate, and isocytrate by oxygen in the presence of NAD(P)-dependent oxidoreductases and 4-anilino-5-methoxybenzoquinone-1,2 was studied. A complete reaction sequence includes (1) oxidoreduction of a corresponding substrate with a specific NAD(P)-dependent dehydrogenase and formation of NAD(P)H (2) reduction of AMOBQ, AMOBQHa formation in the oxidoreduction of NAD(P)H and AMOBQ, catalized by menadione reructase (EC 1.6.99.2); (3) oxygen reduction with AMOBQH2 in a spontaneous or enzymic reaction. AMOBQ plays a catalytic role in the transfer of reducing equivalents to oxygen in the above--menshioned systems. Possible biochemical mechanism for aminoaromatic ortho-benzoquinone derivatives is discussed.