RT Journal Article SR Electronic T1 Characteristics of a Microsomal Dechlorination System JF Molecular Pharmacology JO Mol Pharmacol FD American Society for Pharmacology and Experimental Therapeutics SP 809 OP 817 VO 11 IS 6 A1 RUSSELL A. VAN DYKE A1 A. JAY GANDOLFI YR 1975 UL http://molpharm.aspetjournals.org/content/11/6/809.abstract AB Microsomes were solubilized and the components of the mixed-function oxidase system were isolated. With a reconstituted system containing partially purified cytochrome P-450, NADPH—cytochrome c reductase, NADPH, and phospholipid, dechlorination of 1,1,2-trichloroethane was observed. Addition of cytochrome b5, NADH—cytochrome b5 reductase, and cyanide-sensitive factor to this system resulted in additional activity, but the cytochrome b5 system by itself would not dechlorinate. The activity of the complete system was not altered by the presence of the cyanide-sensitive factor. Whole microsomes also were studied and the kinetics of the dechlorination reaction was determined. The Km was 3.32 mM; Vmax was 1.09 nmoles of substrate dechlorinated per minute per milligram of protein. The addition of NADH to the NADPH system significantly increased both Km and Vmax. The microsomal enzyme system required molecular oxygen; the presence of the cell supernatant fraction produced an increase in the Vmax of dechlorination. ACKNOWLEDGMENT The authors are indebted to Mrs. Rita M. Nelson for her skillful technical assistance.