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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Publicado:	1977
Materias:	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 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
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0039128X_v30_n1_p41_Monsalve http://hdl.handle.net/20.500.12110/paper_0039128X_v30_n1_p41_Monsalve
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_0039128X_v30_n1_p41_Monsalve
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spelling	paper:paper_0039128X_v30_n1_p41_Monsalve2023-06-08T15:03:12Z Partial characterization of epididymal 5α reductase in the rat 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. 1977 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0039128X_v30_n1_p41_Monsalve 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 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.
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
publishDate	1977
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0039128X_v30_n1_p41_Monsalve http://hdl.handle.net/20.500.12110/paper_0039128X_v30_n1_p41_Monsalve
_version_	1768545135079981056

Partial characterization of epididymal 5α reductase in the rat

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