title: Reduction of prostaglandin D2 to 9 alpha,11 beta-prostaglandin F2 by a human liver 3 alpha-hydroxysteroid/dihydrodiol dehydrogenase isozyme.
abstract: Prostaglandin (PG) specificity of two 3 alpha-hydroxysteroid/dihydrodiol dehydrogenase isozymes, DD2 and DD4, of human liver was examined. DD2 exhibited NADPH-linked reductase activity for 9-,11- and 15-ketoprostaglandins at a pH optimum of 6.0, whereas DD4 reduced only 15-ketoprostaglandin F2 alpha. DD2 showed the highest Vmax/Km value for PGD2 of the PG substrates, and the reduced product of PGD2 was identified to 9 alpha,11 beta-PGF2 by gas chromatography-mass spectrometry. In the reverse reaction with NADP+ as a cofactor, the two enzymes slowly oxidized several PGs with 9-, 11- and/or 15-hydroxy groups, except that DD2 showed high activity for 9 alpha,11 beta-PGF2 at a pH optimum of 10.0. The Km and Vmax values of DD2 for PGD2 were 57 microM and 250 nmol/min per mg, respectively, at pH 7.0 and 37 degrees C, and the respective values for 9 alpha,11 beta-PGF2 were 72 microM and 10 nmol/min per mg. PGD2 11-ketoreductase activity in human liver cytosol was recovered in 30-75% saturated ammonium sulfate fraction. More than 77% of the PGD2 11-ketoreductase activity in the ammonium sulfate fraction was immunoprecipitated by antibodies against DD2, and inhibited by known inhibitors of the enzyme. These results suggest that DD2 is a major soluble PGD2 11-ketoreductase species in human liver.
authors.affiliation: Biochemistry Laboratory, Gifu Pharmaceutical University, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ohara
authors.forename: T
authors.initials: T
authors.lastname: Nakayama
authors.forename: Y
authors.initials: Y
authors.lastname: Deyashiki
authors.forename: A
authors.initials: A
authors.lastname: Hara
authors.forename: Y
authors.initials: Y
authors.lastname: Miyabe
authors.forename: F
authors.initials: F
authors.lastname: Tsukada
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D045002:3-alpha-Hydroxysteroid Dehydrogenase (B-Specific); D000429:Alcohol Oxidoreductases / Q000378:metabolism*; D015237:Dinoprost / Q000096:biosynthesis*; D006801:Humans; D006911:Hydroxyprostaglandin Dehydrogenases / Q000378:metabolism*; D007527:Isoenzymes / Q000378:metabolism; D008099:Liver / Q000201:enzymology*; D010084:Oxidation-Reduction; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; D015230:Prostaglandin D2 / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D007527:Isoenzymes; D015237:Dinoprost; D010088:Oxidoreductases; D015096:3-Hydroxysteroid Dehydrogenases; D000429:Alcohol Oxidoreductases; C023125:dihydrodiol dehydrogenases; D006911:Hydroxyprostaglandin Dehydrogenases; C031051:prostaglandin-F synthase; D045002:3-alpha-Hydroxysteroid Dehydrogenase (B-Specific); D044925:Oxidoreductases Acting on CH-CH Group Donors; C116788:cis-1,2-dihydro-1,2-dihydroxynaphthalene dehydrogenase; D015230:Prostaglandin D2