TY - JOUR
T1 - Purification of a vitamin K epoxide reductase that catalyzes conversion of vitamin K 2,3-epoxide to 3-hydroxy-2-methyl-3-phytyl-2,3-dihydronaphthoquinone
AU - Mukharji, I.
AU - Silverman, R. B.
PY - 1985
Y1 - 1985
N2 - An enzyme from bovine liver microsomes that catalyzes the reduction of vitamin K 2,3-epoxide to 2- and 3-hydroxy-2-methyl-3-phytyl-2-dihydronaphthoquinone was purified 1152-fold to apparent homogeneity. Microsomes were solubilized with 3-[3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS), and the enzyme was purified by chromatography on PBE-94 ion exchanger, hydroxylapatite, and DEAE-cellulose, and then gel filtration on Sephacryl S-200. The homogeneity of the final preparation was established by polyacrylamide slab gel electrophoresis in the presence of sodium dodecyl sulfate. The molecular weight of the native enzyme is 25,000 and that of denatured enzyme is 12,400, which suggests that the enzyme is a dimer with identical subunits. No chromophoric cofactors are associated with the enzyme. Dithiothreitol and CHAPS are essential for activity, but high concentrations of glycerol reduces the activity. The enzyme is not inhibited by warfarin, a potent inhibitor of the vitamin K epoxide reductase, which catalyzes the conversion of vitamin K 2,3-epoxide to vitamin K. Evidence is presented indicating that the purified enzyme is not simply a fragment of the warfarin-sensitive vitamin K epoxide reductase.
AB - An enzyme from bovine liver microsomes that catalyzes the reduction of vitamin K 2,3-epoxide to 2- and 3-hydroxy-2-methyl-3-phytyl-2-dihydronaphthoquinone was purified 1152-fold to apparent homogeneity. Microsomes were solubilized with 3-[3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS), and the enzyme was purified by chromatography on PBE-94 ion exchanger, hydroxylapatite, and DEAE-cellulose, and then gel filtration on Sephacryl S-200. The homogeneity of the final preparation was established by polyacrylamide slab gel electrophoresis in the presence of sodium dodecyl sulfate. The molecular weight of the native enzyme is 25,000 and that of denatured enzyme is 12,400, which suggests that the enzyme is a dimer with identical subunits. No chromophoric cofactors are associated with the enzyme. Dithiothreitol and CHAPS are essential for activity, but high concentrations of glycerol reduces the activity. The enzyme is not inhibited by warfarin, a potent inhibitor of the vitamin K epoxide reductase, which catalyzes the conversion of vitamin K 2,3-epoxide to vitamin K. Evidence is presented indicating that the purified enzyme is not simply a fragment of the warfarin-sensitive vitamin K epoxide reductase.
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U2 - 10.1073/pnas.82.9.2713
DO - 10.1073/pnas.82.9.2713
M3 - Article
C2 - 3857611
AN - SCOPUS:0021991836
VL - 82
SP - 2713
EP - 2717
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 9
ER -