Characteristics of rat liver microsomal 3-hydroxy-3-methylglutaryl-coenzyme A reductase

1. A procedure for the preparation of rat liver microsomal fractions essentially devoid of contaminating lysosomes is described. 2. When this preparation was examined by immunoblotting with a rabbit antiserum to rat 3-hydroxy-3-methylglutaryl-CoA reductase, a single band corresponding to an M(r) of 100000 was observed. 3. No evidence was found for glycosylation of rat liver-3-hydroxy-3-methylglutaryl-CoA reductase. 4. Native rat liver microsomal 3-hydroxy-3-methylglutaryl-CoA reductase differs from the purified proteolytically modified species in that it displays allosteric kinetics towards NADPH.