Abstract
3-Hydroxy-3-methylglutaryl coenzyme A reductase (NADPH) was solubilized by trypsin digestion from sliced potato tuber microsomes, and purified to apparent homogeneity in the absence of detergent with a recovery of 1.8%. The enzyme had a specific activity of 7, 910nmol of mevalonate formed per min per mg of protein. On molecular-sieving high-performance liquid chromatography, the activity was coincident with the single protein peak corresponding to a molecular weight of approximately 110kDa. On SDS-polyacrylamide gel electrophoresis, the purified enzyme showed only one protein staining band corresponding to a molecular weight of approximately 55kDa. The apparent Km value for S-HMG-CoA was 6.4μM and that for NADPH was 25μM.
