{"title":"Human placental steroid-sulfatase solubilized with a cholic-acid derivative: molecular mass, kinetic properties and susceptibility to glycosidases.","authors":"L Dibbelt, E Kuss","doi":"10.1515/bchm2.1984.365.2.1145","DOIUrl":null,"url":null,"abstract":"<p><p>Human placental steroid-sulfatase was extracted nearly quantitatively from microsomes as well as from acetone dry powder of placenta homogenates using CHAPS as detergent. The solubilized enzyme was enriched 10-fold by ammonium sulfate precipitation and gel chromatography. The sulfatase extracted from both microsomes and acetone dry powder eluted as a single fraction on Sepharose 6B, but with different apparent molecular masses (390 and 270 kDa, respectively). Kinetic experiments with the sulfate esters of dehydroepiandrosterone, 16 alpha-hydroxydehydroepiandrosterone, estrone, and estriol as substrates or inhibitors indicated that the solubilized sulfatase was fully active. Both the particulate and the extracted enzyme showed higher affinities for the 16-unsubstituted than for the 16 alpha-hydroxylated substrates. Whereas a competitive inhibition was observed in mixed substrate incubations with dehydroepiandrosterone sulfate/16 alpha-hydroxydehydroepiandrosterone sulfate and estrone sulfate/estriol sulfate, diverse patterns of inhibition were obtained with dehydroepiandrosterone sulfate/estrone sulfate, depending on the sulfatase preparation used. However, evidence for the distinct nature of the steroid-sulfatase and the estrogen-sulfatase was not obtained. The membrane-bound, but not the solubilized enzyme was to a certain degree sensitive to lipase and acetone. The solubilized sulfatase strongly bound to ConA-Sepharose. This observation together with the elution by alpha-methyl mannoside were indicative of the presence of carbohydrates on the sulfatase. Since its enzymatic activity was markedly decreased by the effects of alpha-mannosidase and N-acetylglucosaminidase, a possible involvement of the carbohydrate moiety in the catalytic activity of the sulfatase might be considered.</p>","PeriodicalId":13015,"journal":{"name":"Hoppe-Seyler's Zeitschrift fur physiologische Chemie","volume":"365 9","pages":"1145-53"},"PeriodicalIF":0.0000,"publicationDate":"1984-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/bchm2.1984.365.2.1145","citationCount":"14","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Hoppe-Seyler's Zeitschrift fur physiologische Chemie","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1515/bchm2.1984.365.2.1145","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 14
Abstract
Human placental steroid-sulfatase was extracted nearly quantitatively from microsomes as well as from acetone dry powder of placenta homogenates using CHAPS as detergent. The solubilized enzyme was enriched 10-fold by ammonium sulfate precipitation and gel chromatography. The sulfatase extracted from both microsomes and acetone dry powder eluted as a single fraction on Sepharose 6B, but with different apparent molecular masses (390 and 270 kDa, respectively). Kinetic experiments with the sulfate esters of dehydroepiandrosterone, 16 alpha-hydroxydehydroepiandrosterone, estrone, and estriol as substrates or inhibitors indicated that the solubilized sulfatase was fully active. Both the particulate and the extracted enzyme showed higher affinities for the 16-unsubstituted than for the 16 alpha-hydroxylated substrates. Whereas a competitive inhibition was observed in mixed substrate incubations with dehydroepiandrosterone sulfate/16 alpha-hydroxydehydroepiandrosterone sulfate and estrone sulfate/estriol sulfate, diverse patterns of inhibition were obtained with dehydroepiandrosterone sulfate/estrone sulfate, depending on the sulfatase preparation used. However, evidence for the distinct nature of the steroid-sulfatase and the estrogen-sulfatase was not obtained. The membrane-bound, but not the solubilized enzyme was to a certain degree sensitive to lipase and acetone. The solubilized sulfatase strongly bound to ConA-Sepharose. This observation together with the elution by alpha-methyl mannoside were indicative of the presence of carbohydrates on the sulfatase. Since its enzymatic activity was markedly decreased by the effects of alpha-mannosidase and N-acetylglucosaminidase, a possible involvement of the carbohydrate moiety in the catalytic activity of the sulfatase might be considered.