Endocrine steroid sulfotransferases: steroid alcohol sulfotransferase from human breast carcinoma cell line MCF-7.
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| Abstract |
Steroid alcohol sulfotransferase (SAS) has been isolated from the cytosol of a human breast carcinoma cell line, MCF-7. This enzyme from Sephadex G-200 chromatography displayed a mol. wt of 118 KDa. The conditions for optimal enzymic activity of SAS were determined to be 20 min incubations at 45 degrees C in 0.2 M Tris buffer (pH 7.5) containing 0.06 M Mg2+. Chromatofocusing chromatography also yielded a single peak of SAS with a pI of 5.8. Results from the incubations of a series of androstane analogues revealed that SAS required a 3 beta-hydroxyl on a steroid with the trans bridge between the A and B rings. Neither the 3 beta-allylic hydroxyl group nor the A-ring phenolic 3-hydroxyl accepted the sulfate group from 3'-phosphoadenosine-5'-phosphosulfate. D-ring beta-hydroxyl groups were tolerated by the enzyme, however, alpha-hydroxyl groups on the D-ring appeared to interfere with the reaction. Sulfurylation of steroids by SAS was related inversely to the sum of the displacements of the 3-hydroxyl plus that of the 17-hydroxyl groups relative to the plane of symmetry of the dehydroepiandrosterone nucleus. This enzyme was also capable of sulfurylating short chain aliphatic alcohols, although at greatly reduced rates. 3 beta-Chloro-5-androstene-17-one and 2-nitroestradiol. 17 beta proved to be the best inhibitors of SAS.
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| Authors | J Rozhin, J D Corombos, J P Horwitz, S C Brooks |
| Journal | Journal of steroid biochemistry (J Steroid Biochem) Vol. 25 Issue 6 Pg. 973-9 (Dec 1986) ISSN: 0022-4731 [Print] England |
| PMID | 2948075 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.) |
| Chemical References |
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