hydroxysteroid 17-beta dehydrogenase 6 (17-beta-HSD6, oxidative 3-alpha hydroxysteroid dehydrogenase, 3-alpha->beta-hydroxysteroid epimerase, 3-alpha->beta-HSE, HSD17B6, RODH)

Function: - NAD-dependent oxidoreductase with broad substrate specificity - shows both oxidative & reductive activity (in vitro) - has 17-beta-hydroxysteroid dehydrogenase activity towards various steroids (in vitro) - converts 5-alpha-androstan-3-alpha,17-beta-diol to androsterone & estradiol to estrone (in vitro) - 3-alpha-hydroxysteroid dehydrogenase activity towards androsterone (in vitro) - has retinol dehydrogenase activity towards all-trans-retinol (in vitro) - can convert androsterone to epi-androsterone - androsterone is first oxidized to 5-alpha-androstane-3,17-dione & then reduced to epi-andosterone - can act on both C-19 & C-21 3-alpha-hydroxysteroids estradiol-17-beta + NAD+/NADP+ estrone + NADH/NADPH testosterone + NAD+ androst-4-ene-3,17-dione + NADH retinol + NAD+ retinal + NADH Kinetic parameters: - KM=0.19 uM for NAD - KM=0.18 uM for NADH - KM=54 uM for NADPH - KM=940 uM for NADP - KM=3.2 uM for all-trans-retinol - KM=0.24 uM for allopregnanolone - KM=0.13 uM for 3-alpha-androstanediol - KM=0.23 uM for androsterone - KM=0.13 uM for dehydroepiandrosterone - Vmax=1.2 nmol/min/mg enzyme with all-trans-retinol - Vmax=14.7 nmol/min/mg enzyme with allopregnanolone - Vmax=16.5 nmol/min/mg enzyme with 3-alpha-androstanediol - Vmax=35 nmol/min/mg enzyme with androsterone - Vmax=0.90 nmol/min/mg enzyme with dehydroepiandrosterone Note: - kinetic parameters determined using microsomes from transfected cells Structure: - belongs to the short-chain dehydrogenases/reductases (SDR) family Compartment: microsome, lumenal side Expression: - detected in liver & prostate (at protein level) - detected in adult liver, lung, brain, placenta, prostate, adrenal gland, testis, mammary gland, spleen, spinal cord & uterus. - detected in caudate nucleus, & at lower levels in amygdala, corpus callosum, hippocampus, substantia nigra & thalamus - detected in fetal lung, liver & brain

General

glycoprotein hydroxysteroid dehydrogenase

Properties

SIZE: entity length = 317 aa MW = 36 kD MOTIF: signal sequence {1-17} N-glycosylation site {N161} active site binding site SITE: 164-164 FOR-BINDING-OF: Substrate tyrosine residue {Y176} N-glycosylation site {N215} N-glycosylation site {N256}

Database Correlations

OMIM 606623 UniProt O14756 Pfam PF00106 ENZYME correlations

References

UniProt :accession O14756