4-Nitrobenzoic acid reductase of the nematode Ascaris lumbricoides var suum. Localization of the enzyme and optimum assay conditions.
1. Reduction of 4-nitrobenzoic acid by the nematode Ascaris lumbricoides var suum occurred in the intestinal brush border cells. Cuticle, mesenchyme fluid and reproductive tissue showed no activity. 2. 4-Nitrobenzoic acid reductase was in the supernatant fraction after centrifugation of intestinal homogenates at 75 000 g for 2 h. 3. The enzyme required as cofactors NADH2, a low molecular weight thiol such as glutathione or cysteine and a divalent metal ion such as Mn++ or Cu++. The reduction  was not catalysed by NADPH2. 4. Reduction was not inhibited by O2 or CO. Optimum pH of the reaction was about 6.5.
D000818:Animals; D001200:Ascaris / Q000201:enzymology* / Q000378:metabolism; D002413:Cations, Divalent; D002458:Cell Fractionation; D003545:Cysteine / Q000378:metabolism; D003593:Cytoplasm / Q000201:enzymology; D005260:Female; D005590:Fractional Precipitation; D005978:Glutathione / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007422:Intestines / Q000201:enzymology; D008297:Male; D008670:Metals / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D009579:Nitrobenzoates / Q000378:metabolism; D010088:Oxidoreductases / Q000032:analysis*
D002413:Cations, Divalent; D008670:Metals; D009579:Nitrobenzoates; D009243:NAD; D010088:Oxidoreductases; D005978:Glutathione; D003545:Cysteine