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Information on EC 1.1.1.145 - 3beta-hydroxy-DELTA5-steroid dehydrogenase

for references in articles please use BRENDA:EC1.1.1.145

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IUBMB Comments

This activity is found in several bifunctional enzymes that catalyse the oxidative conversion of Δ5-3-hydroxy steroids to a Δ4-3-oxo configuration. This conversion is carried out in two separate, sequential reactions; in the first reaction, which requires NAD+, the enzyme catalyses the dehydrogenation of the 3β-hydroxy steroid to a 3-oxo intermediate. In the second reaction the reduced coenzyme, which remains attached to the enzyme, activates the isomerization of the Δ5 form to a Δ4 form (cf. EC 5.3.3.1, steroid Δ-isomerase). Substrates include dehydroepiandrosterone (which is converted into androst-5-ene-3,17-dione), pregnenolone (converted to progesterone) and cholest-5-en-3-one, an intermediate of cholesterol degradation.

The enzyme appears in viruses and cellular organisms

Synonyms
hsd3b2, hsd3b, dhrs4, 3-beta-hydroxysteroid dehydrogenase, hsd3b6, 3betahsd2, 3beta hydroxysteroid dehydrogenase, 3beta-hydroxysteroid dehydrogenase type ii, 3beta-hydroxysteroid dehydrogenase type 2, 3beta-hsd type ii, more

REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
a 3beta-hydroxy-DELTA5-steroid + NAD+ = a 3-oxo-DELTA5-steroid + NADH + H+
show the reaction diagram
PATHWAY SOURCE
PATHWAYS
MetaCyc
11-oxyandrogens biosynthesis, androgen biosynthesis, androstenedione degradation I (aerobic), androstenedione degradation II (anaerobic), backdoor pathway of androgen biosynthesis, cholesterol degradation to androstenedione II (cholesterol dehydrogenase), cholesterol degradation to androstenedione III (anaerobic), progesterone biosynthesis, sitosterol degradation to androstenedione