title: Expression in E. coli and tissue distribution of the human homologue of the mouse Ke 6 gene, 17beta-hydroxysteroid dehydrogenase type 8.
abstract: Expression of the human Ke 6 gene, 17beta-hydroxysteroid dehydrogenase type 8, in E. coli and the substrate specificity of the expressed protein were examined. The tissue distribution of mRNA expression of the human Ke 6 gene was also studied using real-time PCR. Human Ke 6 gene was expressed as an enzymatically-active His-tag fusion protein, whose molecular weight was estimated to be 32.5 kDa by SDS-polyacrylamide gel electrophoresis. Expressed human Ke 6 gene effectively catalyzed the conversion of estradiol into estrone. Testosterone, 5alpha-dihydrotestosterone, and 5-androstene-3beta,17beta-diol were also catalyzed into the corresponding 17-ketosteroid at 2.4-5.9% that of estradiol oxidation. Furthermore, expressed enzyme catalyzed the reduction of estrone to estradiol, but the rate was a mere 2.3%. Human Ke 6 gene mRNA was expressed in the various tissues examined, such as brain, cerebellum, heart, lung, kidney, liver, small intestine, ovary, testis, adrenals, placenta, prostate, and stomach. Expression of human Ke 6 gene mRNA was especially abundant in prostate, placenta, and kidney. The levels in prostate and placenta were higher than that in kidney, where it is known to be expressed in large quantities.
authors.affiliation: Department of Biochemistry, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa, Tokyo 142-8501, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Ohno
authors.forename: Kouki
authors.initials: K
authors.lastname: Nishikawa
authors.forename: Yoko
authors.initials: Y
authors.lastname: Honda
authors.forename: Shizuo
authors.initials: S
authors.lastname: Nakajin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D004926:Escherichia coli / Q000378:metabolism*; D005260:Female; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007700:Kinetics; D008297:Male; D051379:Mice; D008875:Middle Aged; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D013379:Substrate Specificity; D013997:Time Factors
chemical_list: C102228:HSD17B8 protein, human; D011506:Proteins; D012333:RNA, Messenger; D010088:Oxidoreductases