Purification and some characteristics of an oestrogen sulphotransferase from guinea pig adrenal gland and its non-identity with adrenal pregnenolone sulphotransferase

Abstract

An oestrogen sulphotransferase, active towards both oestrone and oestradiol, and of high specific activity, is present in cytosol prepared from adrenal glands of both sexes of English Shorthair and Hartley guinea pigs. The ovarian and testicular cytosolic activities of this enzyme are markedly low in comparison with the adrenal activity. The adrenal enzyme is distinct from an accompanying pregnenolone sulphotransferase as judged by f.p.l.c. gel filtration, chromatofocusing, and differences in activation brought about by the addition of thiol groups. The oestrogen sulphotransferase behaved as a 67 kDa protein on a Sephadex G100 column and as a 48 kDa protein on f.p.l.c. gel-filtration columns. Two forms of the enzyme with apparent pI values of 6.1 and 5.5 were eluted during f.p.l.c. chromatofocusing. Sequential salt fractionation, f.p.l.c. gel filtration and elution from an agarose-hexane-adenosine-3',5'-diphosphate affinity gel has resulted in a preparation which, when resubmitted to f.p.l.c. gel filtration, yields a considerably purified oestrogen sulphotransferase. When submitted to SDS/polyacrylamide-gel electrophoresis under reducing conditions, a main protein band of 34-36 kDa is observed. It is suggested that the enzyme may exist as a dimer in the cytosol.

Steroid Sulfotransferases

“…Furthermore, EST in the male rat liver is expressed only after puberty, localizing to specific hepatocytes around the central vein where it is present in selective nuclei of perivenous cells (123). EST activity is highly expressed in the guinea pig adrenal cortex (124): by immunocytochemistry it is present in both the zona fasciculata and zona reticularis, where it localizes to cellular nuclei as well as the cytoplasmic compartment (125). EST, interestingly, is not expressed by cells in the zona glomerulosa (125).…”

An unusually small dimer interface is observed in all available crystal structures of cytosolic sulfotransferases

“…Experimental data indicating dimer formation are available for human SULT1A14, rat SULT1A15,6, human SULT1A37, human SULT1E18, Guinea pig SULT1E19, hamster SULT2A110, human SULT2A111, rat SULT2A112, human SULT2A313, and C. elegans ST114. Petrotchenko et al8 used a combination of cross-linking reagents, protease digestion, and mass spectrometry to identify peptides involved in the dimerization interface of human SULT1A3.…”

Cloning and expression of human liver dehydroepiandrosterone sulphotransferase

“…and bile acids have been isolated and characterized from rodent, guinea pig, and bovine liver or adrenal tissue [10][11][12][13]. These enzymes represent a heterogeneous family of isoenzymes that often have different, but overlapping, substrate specificities [14,15].…”