Expression and characterization of the human 3 beta-hydroxysteroid sulfotransferases (SULT2B1a and SUMB1b)

The human hydroxysteroid sulfotransferase, dehydroepiandrosterone sulfotran sferase (DHEA-ST), is highly expressed in liver and adrenal cortex and disp lays reactivity towards a broad range of hydroxysteroids including 3 beta - hydroxysteroids, 3 alpha -hydroxysteroids, estrogens with a 3-phenolic moie ty, and 17-hydroxyl group of androgens. In contrast, characterization of th e newly described human hydroxysteroid sulfotransferase SULT2B1 isoforms sh ows that these enzymes are selective for the sulfation of 3 beta -hydroxyst eroids, such as pregnenolone, epiandrosterone, DHEA, and androstenediol. Th ere was no activity detected towards testosterone, dexamethasone, beta -est radiol, androsterone, or p-nitrophenol. The SULT2B1 gene encodes two isofor ms, SULT2131a and SULT2B1b, which are generated by alternate splicing of th e first exon; therefore the SULT2B1 isoforms differ at their N-terminals. N orthern Blot analysis detected a SULT2B1 message in RNA isolated from the h uman prostate and placenta. No SULT2B1 message was observed in RNA isolated from human liver, colon, lung, kidney, brain, or testis tissue. Purified S ULT2B1a was used to generate a specific rabbit polyclonal anti-SULT2B1 anti body. The anti-SULT2B1 antibody did not react with expressed human EST, P-P ST-1, M-PST, DHEA-ST, or ST1B2, during immunoblot analysis. The substrate s pecificity of the expressed SULT2B1 isoforms suggests that these enzymes ar e capable of regulating the activity of adrenal androgens in human tissues via their inactivation by sulfation. (C) 2001 Elsevier Science Ltd. All rig hts reserved.