Subcellular localization of 3β hydroxysteroid dehydrogenase isomerase in testis of Bufo arenarum H.
3β-hydroxysteroid dehydrogenase 5-ene isomerase (3βHSD/I) catalyzes an essential step in the biosynthesis of steroid hormones and is usually considered to be mainly microsomal, although there is a dual distribution of the enzyme in toad interrenals. The present study demonstrates that in the testicu...
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1997
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00166480_v106_n3_p400_Pozzi http://hdl.handle.net/20.500.12110/paper_00166480_v106_n3_p400_Pozzi |
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paper:paper_00166480_v106_n3_p400_Pozzi2025-07-30T17:20:55Z Subcellular localization of 3β hydroxysteroid dehydrogenase isomerase in testis of Bufo arenarum H. 3(or 17)beta hydroxysteroid dehydrogenase androstenedione isomerase prasterone pregnenolone animal tissue article enzyme localization enzyme substrate hormone synthesis microsome mitochondrion nonhuman priority journal steroidogenesis testis toad 3β-hydroxysteroid dehydrogenase 5-ene isomerase (3βHSD/I) catalyzes an essential step in the biosynthesis of steroid hormones and is usually considered to be mainly microsomal, although there is a dual distribution of the enzyme in toad interrenals. The present study demonstrates that in the testicular tissue, as in interrenals of Bufo arenarum H., 3βHSD/I is both mitochondrial and microsomal. The conversion of dehydroepiandrosterone to androstenedione takes place only in microsomes while pregnenolone is converted to progesterone in both microsomes and mitochondria. Kinetic constants of 3βHSD/I were determined by the oxidation of pregnenolone and dehydroepiandrosterone. The preferred substrate of the microsomal 3βHSD/I enzyme was dehydroepiandrosterone (K(m) = 0.17 μM and 0.53 μM for dehydroepiandrosterone and pregnenolone, respectively) not only during the breeding season but also in the nonbreeding period (K(m) = 0.49 μM and 2.9 μM for dehydroepiandrosterone and pregnenolone, respectively). 1997 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00166480_v106_n3_p400_Pozzi http://hdl.handle.net/20.500.12110/paper_00166480_v106_n3_p400_Pozzi |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
3(or 17)beta hydroxysteroid dehydrogenase androstenedione isomerase prasterone pregnenolone animal tissue article enzyme localization enzyme substrate hormone synthesis microsome mitochondrion nonhuman priority journal steroidogenesis testis toad |
| spellingShingle |
3(or 17)beta hydroxysteroid dehydrogenase androstenedione isomerase prasterone pregnenolone animal tissue article enzyme localization enzyme substrate hormone synthesis microsome mitochondrion nonhuman priority journal steroidogenesis testis toad Subcellular localization of 3β hydroxysteroid dehydrogenase isomerase in testis of Bufo arenarum H. |
| topic_facet |
3(or 17)beta hydroxysteroid dehydrogenase androstenedione isomerase prasterone pregnenolone animal tissue article enzyme localization enzyme substrate hormone synthesis microsome mitochondrion nonhuman priority journal steroidogenesis testis toad |
| description |
3β-hydroxysteroid dehydrogenase 5-ene isomerase (3βHSD/I) catalyzes an essential step in the biosynthesis of steroid hormones and is usually considered to be mainly microsomal, although there is a dual distribution of the enzyme in toad interrenals. The present study demonstrates that in the testicular tissue, as in interrenals of Bufo arenarum H., 3βHSD/I is both mitochondrial and microsomal. The conversion of dehydroepiandrosterone to androstenedione takes place only in microsomes while pregnenolone is converted to progesterone in both microsomes and mitochondria. Kinetic constants of 3βHSD/I were determined by the oxidation of pregnenolone and dehydroepiandrosterone. The preferred substrate of the microsomal 3βHSD/I enzyme was dehydroepiandrosterone (K(m) = 0.17 μM and 0.53 μM for dehydroepiandrosterone and pregnenolone, respectively) not only during the breeding season but also in the nonbreeding period (K(m) = 0.49 μM and 2.9 μM for dehydroepiandrosterone and pregnenolone, respectively). |
| title |
Subcellular localization of 3β hydroxysteroid dehydrogenase isomerase in testis of Bufo arenarum H. |
| title_short |
Subcellular localization of 3β hydroxysteroid dehydrogenase isomerase in testis of Bufo arenarum H. |
| title_full |
Subcellular localization of 3β hydroxysteroid dehydrogenase isomerase in testis of Bufo arenarum H. |
| title_fullStr |
Subcellular localization of 3β hydroxysteroid dehydrogenase isomerase in testis of Bufo arenarum H. |
| title_full_unstemmed |
Subcellular localization of 3β hydroxysteroid dehydrogenase isomerase in testis of Bufo arenarum H. |
| title_sort |
subcellular localization of 3β hydroxysteroid dehydrogenase isomerase in testis of bufo arenarum h. |
| publishDate |
1997 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00166480_v106_n3_p400_Pozzi http://hdl.handle.net/20.500.12110/paper_00166480_v106_n3_p400_Pozzi |
| _version_ |
1840321662435721216 |