Sunflower Nitrate Reductase: Purification and Characterization

摘要

A single isoform, NADH: nitrate reductase(NR), was purified 500 folds from sunflower leaves by affinity chromatography on Blue Sepharose CL-6B. Purified NR had a pH optima of 7.25 and a molecular weight of 210 kD. In SDS-PAGE,two bands of 47 and 56 kD were obtained. NADH: ferric citrate reductase activity was copurified with NR with a specific activity of 2. The Vmax of NADH: ferric citrate reductase was 8.69 units mg~-1 protein and the apparent Km for ferric citrate was 0.435 mM.