{"title":"Reinigung und charakterisierung einer löslichen uridin diphosphat-glucuronat: 17β-hydroxysteroid-glucuronyl-transferase beim menschen","authors":"K Dahm, H Breuer","doi":"10.1016/0926-6593(66)90177-9","DOIUrl":null,"url":null,"abstract":"<div><p>The ground plasma (150 000 × <em>g</em> supernatant) of the human intestine contains a uridinediphosphate glucuronate glucuronyltransferase (EC 2.4.1.17) which catalyses exclusively the formation of 17β-glucuronides of oestriol, 17β-oestradiol and testosterone. This enzyme was found in the fractions obtained between 60 and 80% saturation of the ground plasma with ammonium sulphate; it could be separated from two other uridine diphosphate glucuronate glucuronyltransferases which, with oestriol as substrate, were capable of forming the 3-glucuronide and the 16α-glucuronide. The two latter enzymes were present in the fractions obtained at 0–30% and 30–60% saturation of the ground plasma with ammonium sulphate. The low specific activity of the enzyme catalysing the formation of the 3-glucuronide suggests the probability of its origin by microsomal leakage.</p><p>The kinetics of the uridinediphosphate glucuronate: 17β-hydroxysteroid glucuronyltransferase are described. The formation of the 17β-glucuronide of oestriol shows a maximum at pH 6.8. The Michaelis-Menten constant was found to be 3.5 · 10<sup>−4</sup>M, whereas the activation energy of the enzyme amounted to 12.2 kcal/mole.</p></div>","PeriodicalId":100160,"journal":{"name":"Biochimica et Biophysica Acta (BBA) - Enzymology and Biological Oxidation","volume":"128 2","pages":"Pages 306-316"},"PeriodicalIF":0.0000,"publicationDate":"1966-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0926-6593(66)90177-9","citationCount":"10","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Biochimica et Biophysica Acta (BBA) - Enzymology and Biological Oxidation","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/0926659366901779","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 10
Abstract
The ground plasma (150 000 × g supernatant) of the human intestine contains a uridinediphosphate glucuronate glucuronyltransferase (EC 2.4.1.17) which catalyses exclusively the formation of 17β-glucuronides of oestriol, 17β-oestradiol and testosterone. This enzyme was found in the fractions obtained between 60 and 80% saturation of the ground plasma with ammonium sulphate; it could be separated from two other uridine diphosphate glucuronate glucuronyltransferases which, with oestriol as substrate, were capable of forming the 3-glucuronide and the 16α-glucuronide. The two latter enzymes were present in the fractions obtained at 0–30% and 30–60% saturation of the ground plasma with ammonium sulphate. The low specific activity of the enzyme catalysing the formation of the 3-glucuronide suggests the probability of its origin by microsomal leakage.
The kinetics of the uridinediphosphate glucuronate: 17β-hydroxysteroid glucuronyltransferase are described. The formation of the 17β-glucuronide of oestriol shows a maximum at pH 6.8. The Michaelis-Menten constant was found to be 3.5 · 10−4M, whereas the activation energy of the enzyme amounted to 12.2 kcal/mole.