Partial characterization of epididymal 5α reductase in the rat
Epididymal 5α reductase activity was found distributed in the crude nuclear fraction (44%) and microsomal fraction (41%). Spermatozoa contaminating the nuclear preparation accounted for only 3% of its activity. There were no regional differences in the distribution of total 5α reductase activity. Ho...
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todo:paper_0039128X_v30_n1_p41_Monsalve2023-10-03T14:49:20Z Partial characterization of epididymal 5α reductase in the rat Monsalve, A. Blaquier, J.A. steroid reductase divalent cation nicotinamide adenine dinucleotide phosphate oxidoreductase steroid 5alpha reductase Testosterone 5 alpha Reductase enzyme localization epididymis in vitro study rat theoretical study animal article cell fractionation enzymology epididymis kinetics male metabolism pH spermatozoon temperature Animal Cations, Divalent Epididymis Hydrogen-Ion Concentration Kinetics Male NADP Oxidoreductases Rats Spermatozoa Subcellular Fractions Temperature Testosterone 5-alpha-Reductase Epididymal 5α reductase activity was found distributed in the crude nuclear fraction (44%) and microsomal fraction (41%). Spermatozoa contaminating the nuclear preparation accounted for only 3% of its activity. There were no regional differences in the distribution of total 5α reductase activity. However, the nuclear enzyme was more active in caput than in other regions. Maximal activity was found at pH 6.2 and at 32°C. Both enzymes had an absolute requirement of reduced dinucleotides. The microsomal preparation could only use NADPH while the nuclear enzyme could use NADPH and NADH. The apparent Km for the microsomal preparation was 0.62 ± 0.05 × 10-6M and Vmax was 555 ± 38 pmoles/mg protein/hour. The nuclear enzyme presented similar values. The reaction was not inhibited by accumulation of product in the medium, but other steroids such as progesterone, epitestosterone(17α-hydroxy-4-androsten-3-one) and 3-oxo-4-androstene-17β-carboxylic acid were potent competitive inhibitors. The reaction was strongly inhibited by Hg, Zn and Cu. The properties of the epididymal reductase are similar to those of the prostatic enzyme. © 1977. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_0039128X_v30_n1_p41_Monsalve |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
steroid reductase divalent cation nicotinamide adenine dinucleotide phosphate oxidoreductase steroid 5alpha reductase Testosterone 5 alpha Reductase enzyme localization epididymis in vitro study rat theoretical study animal article cell fractionation enzymology epididymis kinetics male metabolism pH spermatozoon temperature Animal Cations, Divalent Epididymis Hydrogen-Ion Concentration Kinetics Male NADP Oxidoreductases Rats Spermatozoa Subcellular Fractions Temperature Testosterone 5-alpha-Reductase |
| spellingShingle |
steroid reductase divalent cation nicotinamide adenine dinucleotide phosphate oxidoreductase steroid 5alpha reductase Testosterone 5 alpha Reductase enzyme localization epididymis in vitro study rat theoretical study animal article cell fractionation enzymology epididymis kinetics male metabolism pH spermatozoon temperature Animal Cations, Divalent Epididymis Hydrogen-Ion Concentration Kinetics Male NADP Oxidoreductases Rats Spermatozoa Subcellular Fractions Temperature Testosterone 5-alpha-Reductase Monsalve, A. Blaquier, J.A. Partial characterization of epididymal 5α reductase in the rat |
| topic_facet |
steroid reductase divalent cation nicotinamide adenine dinucleotide phosphate oxidoreductase steroid 5alpha reductase Testosterone 5 alpha Reductase enzyme localization epididymis in vitro study rat theoretical study animal article cell fractionation enzymology epididymis kinetics male metabolism pH spermatozoon temperature Animal Cations, Divalent Epididymis Hydrogen-Ion Concentration Kinetics Male NADP Oxidoreductases Rats Spermatozoa Subcellular Fractions Temperature Testosterone 5-alpha-Reductase |
| description |
Epididymal 5α reductase activity was found distributed in the crude nuclear fraction (44%) and microsomal fraction (41%). Spermatozoa contaminating the nuclear preparation accounted for only 3% of its activity. There were no regional differences in the distribution of total 5α reductase activity. However, the nuclear enzyme was more active in caput than in other regions. Maximal activity was found at pH 6.2 and at 32°C. Both enzymes had an absolute requirement of reduced dinucleotides. The microsomal preparation could only use NADPH while the nuclear enzyme could use NADPH and NADH. The apparent Km for the microsomal preparation was 0.62 ± 0.05 × 10-6M and Vmax was 555 ± 38 pmoles/mg protein/hour. The nuclear enzyme presented similar values. The reaction was not inhibited by accumulation of product in the medium, but other steroids such as progesterone, epitestosterone(17α-hydroxy-4-androsten-3-one) and 3-oxo-4-androstene-17β-carboxylic acid were potent competitive inhibitors. The reaction was strongly inhibited by Hg, Zn and Cu. The properties of the epididymal reductase are similar to those of the prostatic enzyme. © 1977. |
| format |
JOUR |
| author |
Monsalve, A. Blaquier, J.A. |
| author_facet |
Monsalve, A. Blaquier, J.A. |
| author_sort |
Monsalve, A. |
| title |
Partial characterization of epididymal 5α reductase in the rat |
| title_short |
Partial characterization of epididymal 5α reductase in the rat |
| title_full |
Partial characterization of epididymal 5α reductase in the rat |
| title_fullStr |
Partial characterization of epididymal 5α reductase in the rat |
| title_full_unstemmed |
Partial characterization of epididymal 5α reductase in the rat |
| title_sort |
partial characterization of epididymal 5α reductase in the rat |
| url |
http://hdl.handle.net/20.500.12110/paper_0039128X_v30_n1_p41_Monsalve |
| work_keys_str_mv |
AT monsalvea partialcharacterizationofepididymal5areductaseintherat AT blaquierja partialcharacterizationofepididymal5areductaseintherat |
| _version_ |
1807317263418654720 |