Purification to homogeneity of spinach nitrite reductase by ferredoxin-sepharose affinity chromatography

Assimilatory nitrite reductase was purified 1,700-fold with a yield of 22% from spinach leaves with a procedure involving ammonium sulfate fractionation, DEAE-cellulose and DEAE-Sephadex chromatography, gel filtration and ferredoxin-Sepharose affinity chromatography. The purified enzyme was apparently homogeneous as shown by disc and SDS-gel electrophoresis with a specific activity (mumol NO2-reduced/min/mg protein) of 140.