MIXED-FUNCTION OXIDASES AND NITROREDUCTASES IN HEPATOPANCREAS OF HOMARUS-AMERICANUS

The oxidative activity of the hepatopancreas subcellular fractions was tested using ethylmorphine, biphenyl and aniline substrates. Only aniline was oxidatively hydroxylated. The oxidase activity resided in the soluble fraction, required NADPH and oxygen, and proceeded faster at 20.degree. than 37.degree. C. p-Nitrobenzoic acid was readily reduced to p-aminobenzoic acid by hepatopancreas homogenates. The nitroreductase activity was chiefly in the soluble fraction, and in lesser amounts in the mitochondrial and microsomal fractions; the activity of the latter tended to be unstable. Mitochondrial nitroreductase was more active in the presence of NADH than NADPH. The soluble nitroreductase was most active in the presence of NADPH. NADH dependent nitroreductase of the soluble fraction could be stimulated by addition of FAD or FMN, but the NADPH dependent soluble reductase was inhibited by the flavins.