Purification and characterization of a 3,17 β-hydroxysteroid dehydrogenase from Streptomyces hydrogenans
- 3,17 β-Hydroxysteroid dehydrogenase has been enriched and purified from cytosol of Streptomyces hydrogenans. After ammonium sulfate precipitation and filtration on Sephadex G-100 the enzyme was finally purified by preparative gel electrophoresis and DEAE-Sephadex A-50 chromatography. Polyacrylamide gel electrophoresis in the presence of sodium dodecylsulfate gave a single band of mobility corresponding to molecular weight of 70 200 ± 2 500. 3 β-. 17 β- as well as 20 β-hydroxy steroids were dehydrogenated by the enzyme in the presence of NAD+. The dehydrogenation proceeded faster than the reduction of the corresponding ketosteroids in the presence of NADH. The enzyme does not accent NADP+ or NADPH as co-substrates. The apparent Km values were calculated to be 11 μᴍ for 5 α-dihydrotestosterone, 20 μᴍ for testosterone ana 68 μᴍ for epiandrosterone in the NAD+-driven reaction, 1.8 x 10-4 m for NADH+ and 1.9 x 10-4 ᴍ for NADH. The catalytic activity was influenced by the ratio of NAD+/ATP. The inhibition by ATP appears to be of a competitive type with respect to NAD+ (Ki 1.15 x 10-3 ᴍ). After sucrose gradient centrifugation in a preparative ultracentrifuge the enzyme sediments with 4.1 ± 0.1 S as estimated in comparison to other proteins of known sedimentation coefficient. The isoelectric point was determined to be 3.9 with the LKB preparative isoelectric focusing column (pH 2-11) and 4.1 with the analytical flat bed polyacrylamide isofocusing (pH 3 - 5). The number of SH groups was determined to be 2 mol/mol enzyme. In the presence of 6 M urea the figure inceases to 3 mol SH/mol enzyme. In the presence of an excess of p-chloromercuribenzoate the enzyme activity decreases only partially.
Author: | Helmut Duchmann, Lothar TrägerGND |
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URN: | urn:nbn:de:hebis:30:3-714274 |
DOI: | https://doi.org/10.1515/znc-1979-7-807 |
ISSN: | 0939-5075 |
ISSN: | 1865-7125 |
Parent Title (German): | Zeitschrift für Naturforschung, C |
Publisher: | Verlag der Zeitschrift für Naturforschung |
Place of publication: | Tübingen |
Document Type: | Article |
Language: | English |
Date of Publication (online): | 2014/06/02 |
Year of first Publication: | 1979 |
Publishing Institution: | Universitätsbibliothek Johann Christian Senckenberg |
Release Date: | 2024/01/31 |
Tag: | 20 β-Activity; 3,17 β-Hydroxysteroid Dehydrogenase; Streptomyces hydrogenans |
Volume: | 34.1979 |
Issue: | 7-8 |
Page Number: | 8 |
First Page: | 533 |
Last Page: | 540 |
Institutes: | Biochemie, Chemie und Pharmazie / Biochemie und Chemie |
Dewey Decimal Classification: | 5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften |
5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie | |
Sammlungen: | Universitätspublikationen |
Licence (German): | ![]() |