Involvement of liver aldehyde oxidase in conversion of N-hydroxyurethane to urethane.

K Sugihara, S Kitamura, K Tatsumi

Index: J. Pharmacobiodyn. 6(9) , 677-83, (1983)

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Abstract

The present study provides the evidence that liver aldehyde oxidase in the presence of its electron donors can catalyze the reduction of N-hydroxyurethane to urethane under anaerobic conditions. Guinea pig liver 9000 X g supernatant and cytosol, but not liver microsomes, exhibited N-hydroxyurethane reductase activity in the presence of acetaldehyde or 2-hydroxypyrimidine. The cytosolic enzyme was precipitated with ammonium sulfate between 30 and 45% ammonium sulfate saturation. The N-hydroxyurethane reductase and aldehyde oxidase activities of the precipitate were similarly susceptible to inhibition by a variety of chemicals. When the precipitate was chromatographed on a DEAE-cellulose column, the elution peak position of N-hydroxyurethane reductase was entirely identical with that of aldehyde oxidase. Furthermore, purified rabbit liver aldehyde oxidase also exhibited a significant N-hydroxyurethane reductase activity in the presence of acetaldehyde or 2-hydroxypyrimidine.