Mitochondrial localization of 3β-hydroxysteroid dehydrogenase 5-ene isomerase in interrenals of the toad Bufo arenarum H.

The enzymatic activity of 3β-hydroxysteroid dehydrogenase 5-ene isomerase (3βHSD/I) catalyzes an essential step in the biosynthesis of steroid hormones including progesterone, mineralocorticoids, glucocorticoids, estrogens, and androgens. Its subcellular localization in steroidogenic tissues is usua...

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Autores principales: Pozzi, A.G., Lantos, C.P., Ceballos, N.R.
Formato: JOUR
Materias:
3(or 17)beta hydroxysteroid dehydrogenase
animal tissue
article
cellular distribution
enzyme activity
enzyme localization
male
nonhuman
priority journal
steroidogenesis
tissue distribution
toad
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00166480_v103_n2_p176_Pozzi
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_00166480_v103_n2_p176_Pozzi2023-10-03T14:13:59Z Mitochondrial localization of 3β-hydroxysteroid dehydrogenase 5-ene isomerase in interrenals of the toad Bufo arenarum H. Pozzi, A.G. Lantos, C.P. Ceballos, N.R. 3(or 17)beta hydroxysteroid dehydrogenase animal tissue article cellular distribution enzyme activity enzyme localization male nonhuman priority journal steroidogenesis tissue distribution toad The enzymatic activity of 3β-hydroxysteroid dehydrogenase 5-ene isomerase (3βHSD/I) catalyzes an essential step in the biosynthesis of steroid hormones including progesterone, mineralocorticoids, glucocorticoids, estrogens, and androgens. Its subcellular localization in steroidogenic tissues is usually considered to be mainly microsomal. The present study demonstrates that in the interrenal of Bufo arenarum H., 3βHSD/I activity localizes in mitochondria and micromes. It also shows that the two distinct pathways to aldosterone previously demonstrated for interrenals of B. arenarum H. exhibit differential subcellular localizations, microsomal for the 4-ene route and mitochondrial for the 5- ene route. Kinetic constants of 3βHSD/I were determined for the oxidation of pregnenolone and the recently described 3β-hydroxy analogue of aldosterone (3βAA). The preferred substrate of the mitochondrial 3βHSD/I enzyme was 3βAA (K(m) = 0.7 μM and 14.0 μM for 3βAA and pregnenolone, respectively). However, the microsomal enzyme has a greater affinity for pregnenolone (K(m) = 0.8 μM) than for 3βAA (K(m) = 17.0). Enzymes from both localizations have similar nucleotide (NAD+) requirements, activities being higher in summer. This dual localization opens novel possibilities for the regulation of interrenal functions. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00166480_v103_n2_p176_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
animal tissue
article
cellular distribution
enzyme activity
enzyme localization
male
nonhuman
priority journal
steroidogenesis
tissue distribution
toad
spellingShingle 3(or 17)beta hydroxysteroid dehydrogenase
animal tissue
article
cellular distribution
enzyme activity
enzyme localization
male
nonhuman
priority journal
steroidogenesis
tissue distribution
toad
Pozzi, A.G.
Lantos, C.P.
Ceballos, N.R.
Mitochondrial localization of 3β-hydroxysteroid dehydrogenase 5-ene isomerase in interrenals of the toad Bufo arenarum H.
topic_facet 3(or 17)beta hydroxysteroid dehydrogenase
animal tissue
article
cellular distribution
enzyme activity
enzyme localization
male
nonhuman
priority journal
steroidogenesis
tissue distribution
toad
description The enzymatic activity of 3β-hydroxysteroid dehydrogenase 5-ene isomerase (3βHSD/I) catalyzes an essential step in the biosynthesis of steroid hormones including progesterone, mineralocorticoids, glucocorticoids, estrogens, and androgens. Its subcellular localization in steroidogenic tissues is usually considered to be mainly microsomal. The present study demonstrates that in the interrenal of Bufo arenarum H., 3βHSD/I activity localizes in mitochondria and micromes. It also shows that the two distinct pathways to aldosterone previously demonstrated for interrenals of B. arenarum H. exhibit differential subcellular localizations, microsomal for the 4-ene route and mitochondrial for the 5- ene route. Kinetic constants of 3βHSD/I were determined for the oxidation of pregnenolone and the recently described 3β-hydroxy analogue of aldosterone (3βAA). The preferred substrate of the mitochondrial 3βHSD/I enzyme was 3βAA (K(m) = 0.7 μM and 14.0 μM for 3βAA and pregnenolone, respectively). However, the microsomal enzyme has a greater affinity for pregnenolone (K(m) = 0.8 μM) than for 3βAA (K(m) = 17.0). Enzymes from both localizations have similar nucleotide (NAD+) requirements, activities being higher in summer. This dual localization opens novel possibilities for the regulation of interrenal functions.
format JOUR
author Pozzi, A.G.
Lantos, C.P.
Ceballos, N.R.
author_facet Pozzi, A.G.
Lantos, C.P.
Ceballos, N.R.
author_sort Pozzi, A.G.
title Mitochondrial localization of 3β-hydroxysteroid dehydrogenase 5-ene isomerase in interrenals of the toad Bufo arenarum H.
title_short Mitochondrial localization of 3β-hydroxysteroid dehydrogenase 5-ene isomerase in interrenals of the toad Bufo arenarum H.
title_full Mitochondrial localization of 3β-hydroxysteroid dehydrogenase 5-ene isomerase in interrenals of the toad Bufo arenarum H.
title_fullStr Mitochondrial localization of 3β-hydroxysteroid dehydrogenase 5-ene isomerase in interrenals of the toad Bufo arenarum H.
title_full_unstemmed Mitochondrial localization of 3β-hydroxysteroid dehydrogenase 5-ene isomerase in interrenals of the toad Bufo arenarum H.
title_sort mitochondrial localization of 3β-hydroxysteroid dehydrogenase 5-ene isomerase in interrenals of the toad bufo arenarum h.
url http://hdl.handle.net/20.500.12110/paper_00166480_v103_n2_p176_Pozzi
work_keys_str_mv AT pozziag mitochondriallocalizationof3bhydroxysteroiddehydrogenase5eneisomeraseininterrenalsofthetoadbufoarenarumh
AT lantoscp mitochondriallocalizationof3bhydroxysteroiddehydrogenase5eneisomeraseininterrenalsofthetoadbufoarenarumh
AT ceballosnr mitochondriallocalizationof3bhydroxysteroiddehydrogenase5eneisomeraseininterrenalsofthetoadbufoarenarumh
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