1.3.1.3: DELTA4-3-oxosteroid 5beta-reductase This is an abbreviated version! For detailed information about DELTA4-3-oxosteroid 5beta-reductase, go to the full flat file .
Reaction
17,21-dihydroxy-5beta-pregnane-3,11,20-trione +
NADP+ =
cortisone +
NADPH +
H+
Synonyms 3-oxo-DELTA4-steroid 5beta-reductase, 4,5beta-dihydrocortisone:NADP+ DELTA4-oxidoreductase, 5-beta-reductase, 5beta-POR, 5beta-red, AKR1D1, AKR1D4, aldo-keto reductase, aldo-keto reductase 1D1, aldo–keto reductase 1D1, androstenedione 5beta-reductase, CARUB_v10005016mg, cortisone 5beta-reductase, cortisone beta-reductase, DELTA 4-5beta-reductase, DELTA4-3-ketosteroid 5beta-reductase, DELTA4-3-oxosteroid 5beta-reductase, DELTA4-hydrogenase, EC 1.3.1.23, EC 1.3.1.3, h5beta-red, h5beta-reductase, More, P5betaR, progesterone 5beta-reductase, reductase, cholestenone 5beta.-, reductase, cortisone DELTA4-5beta-, SRD5beta, St5betaR1, steroid 5beta-reductase, steroid 5beta.-reductase, testosterone 5-beta-reductase, testosterone 5beta-reductase
ECTree
General Information
General Information on EC 1.3.1.3 - DELTA4-3-oxosteroid 5beta-reductase
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malfunction
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deficient 5beta-reductase activity can lead to cholestasis and neo-natal liver failure and is often lethal if it remains untreated
evolution
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the enzyme belongs to the aldo–keto reductase (AKR) family, sequence comparisons, overview
evolution
the enzyme belongs to the aldo–keto reductase (AKR) family, sequence comparisons, overview
evolution
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the enzyme is a member of the aldo-keto reductase (AKR) family
physiological function
the enzyme is responsible for steroid hormone 5beta-reduction, as well as for cholic acid and chenodeoxycholic bile-acid synthesis
physiological function
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human steroid 5beta-reductase, i.e. aldo-keto reductase 1D1, catalyzes the stereospecific NADPH-dependent reduction of the C4-C5 double bond of DELTA4-ketosteroids to yield an A/B cis-ring junction. This cis configuration is crucial for bile acid biosynthesis and plays important roles in steroid metabolism. AKR1D1 is the only enzyme necessary for all the 5-steroid metabolites present in humans
physiological function
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the human enzyme, AKR1D1, plays an essential role in bile-acid biosynthesis since the 5beta-configuration is required for the emulsifying properties of bile
additional information
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structure-function relationship, overview
additional information
structure-function relationship, overview
additional information
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existence of a small alternative substrate binding pocket, structure-activity relationship, overview
additional information
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residues Tyr156, Asp205, and Ser248 are responsible for the low catalytic efficiency of the enzyme, substrate binding pocket structure, overview
additional information
the enzyme shows high catalytic efficiency