NADH- and NAD(P)H-Nitrate Reductases in Rice Seedlings

Abstract
By use of affinity chromatography on blue dextran-Sepharose NADH:nitrate oxidoreductase (EC 1.6.6.1) and NAD(P)H:nitrate oxidoreductase (EC 1.6.6.2) from rice (Oryza sativa L.) were partially separted. Nitrate-induced seedlings contained more NADH-nitrate reductase than NAD(P)H-nitrate reductase, whereas chloramphenicol-induced seedlings contained primarily NAD(P)H-nitrate reductase. NAD(P)H-nitrate reductase utilized NADPH directly as reductant. This enzyme has a preference for NADPH, but reacts about half as well with NADH.