Enzymes
| UniProtKB help_outline | 302 proteins |
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- Name help_outline (20S)-hydroxypregn-4-en-3-one Identifier CHEBI:28453 (Beilstein: 5754299,2220567; CAS: 145-14-2) help_outline Charge 0 Formula C21H32O2 InChIKeyhelp_outline RWBRUCCWZPSBFC-RXRZZTMXSA-N SMILEShelp_outline [H][C@@]1(CC[C@@]2([H])[C@]3([H])CCC4=CC(=O)CC[C@]4(C)[C@@]3([H])CC[C@]12C)[C@H](C)O 2D coordinates Mol file for the small molecule Search links Involved in 2 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline NAD+ Identifier CHEBI:57540 (Beilstein: 3868403) help_outline Charge -1 Formula C21H26N7O14P2 InChIKeyhelp_outline BAWFJGJZGIEFAR-NNYOXOHSSA-M SMILEShelp_outline NC(=O)c1ccc[n+](c1)[C@@H]1O[C@H](COP([O-])(=O)OP([O-])(=O)OC[C@H]2O[C@H]([C@H](O)[C@@H]2O)n2cnc3c(N)ncnc23)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 1,186 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,431 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline NADH Identifier CHEBI:57945 (Beilstein: 3869564) help_outline Charge -2 Formula C21H27N7O14P2 InChIKeyhelp_outline BOPGDPNILDQYTO-NNYOXOHSSA-L SMILEShelp_outline NC(=O)C1=CN(C=CC1)[C@@H]1O[C@H](COP([O-])(=O)OP([O-])(=O)OC[C@H]2O[C@H]([C@H](O)[C@@H]2O)n2cnc3c(N)ncnc23)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 1,116 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline progesterone Identifier CHEBI:17026 (Beilstein: 1915950; CAS: 57-83-0) help_outline Charge 0 Formula C21H30O2 InChIKeyhelp_outline RJKFOVLPORLFTN-LEKSSAKUSA-N SMILEShelp_outline [H][C@@]12CCC3=CC(=O)CC[C@]3(C)[C@@]1([H])CC[C@]1(C)[C@H](CC[C@@]21[H])C(C)=O 2D coordinates Mol file for the small molecule Search links Involved in 15 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:42108 | RHEA:42109 | RHEA:42110 | RHEA:42111 | |
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| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
| UniProtKB help_outline |
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Publications
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Human 3alpha-hydroxysteroid dehydrogenase isoforms (AKR1C1-AKR1C4) of the aldo-keto reductase superfamily: functional plasticity and tissue distribution reveals roles in the inactivation and formation of male and female sex hormones.
Penning T.M., Burczynski M.E., Jez J.M., Hung C.F., Lin H.K., Ma H., Moore M., Palackal N., Ratnam K.
The kinetic parameters, steroid substrate specificity and identities of reaction products were determined for four homogeneous recombinant human 3alpha-hydroxysteroid dehydrogenase (3alpha-HSD) isoforms of the aldo-keto reductase (AKR) superfamily. The enzymes correspond to type 1 3alpha-HSD (AKR1 ... >> More
The kinetic parameters, steroid substrate specificity and identities of reaction products were determined for four homogeneous recombinant human 3alpha-hydroxysteroid dehydrogenase (3alpha-HSD) isoforms of the aldo-keto reductase (AKR) superfamily. The enzymes correspond to type 1 3alpha-HSD (AKR1C4), type 2 3alpha(17beta)-HSD (AKR1C3), type 3 3alpha-HSD (AKR1C2) and 20alpha(3alpha)-HSD (AKR1C1), and share at least 84% amino acid sequence identity. All enzymes acted as NAD(P)(H)-dependent 3-, 17- and 20-ketosteroid reductases and as 3alpha-, 17beta- and 20alpha-hydroxysteroid oxidases. The functional plasticity of these isoforms highlights their ability to modulate the levels of active androgens, oestrogens and progestins. Salient features were that AKR1C4 was the most catalytically efficient, with k(cat)/K(m) values for substrates that exceeded those obtained with other isoforms by 10-30-fold. In the reduction direction, all isoforms inactivated 5alpha-dihydrotestosterone (17beta-hydroxy-5alpha-androstan-3-one; 5alpha-DHT) to yield 5alpha-androstane-3alpha,17beta-diol (3alpha-androstanediol). However, only AKR1C3 reduced Delta(4)-androstene-3,17-dione to produce significant amounts of testosterone. All isoforms reduced oestrone to 17beta-oestradiol, and progesterone to 20alpha-hydroxy-pregn-4-ene-3,20-dione (20alpha-hydroxyprogesterone). In the oxidation direction, only AKR1C2 converted 3alpha-androstanediol to the active hormone 5alpha-DHT. AKR1C3 and AKR1C4 oxidized testosterone to Delta(4)-androstene-3,17-dione. All isoforms oxidized 17beta-oestradiol to oestrone, and 20alpha-hydroxyprogesterone to progesterone. Discrete tissue distribution of these AKR1C enzymes was observed using isoform-specific reverse transcriptase-PCR. AKR1C4 was virtually liver-specific and its high k(cat)/K(m) allows this enzyme to form 5alpha/5beta-tetrahydrosteroids robustly. AKR1C3 was most prominent in the prostate and mammary glands. The ability of AKR1C3 to interconvert testosterone with Delta(4)-androstene-3,17-dione, but to inactivate 5alpha-DHT, is consistent with this enzyme eliminating active androgens from the prostate. In the mammary gland, AKR1C3 will convert Delta(4)-androstene-3,17-dione to testosterone (a substrate aromatizable to 17beta-oestradiol), oestrone to 17beta-oestradiol, and progesterone to 20alpha-hydroxyprogesterone, and this concerted reductive activity may yield a pro-oesterogenic state. AKR1C3 is also the dominant form in the uterus and is responsible for the synthesis of 3alpha-androstanediol which has been implicated as a parturition hormone. The major isoforms in the brain, capable of synthesizing anxiolytic steroids, are AKR1C1 and AKR1C2. These studies are in stark contrast with those in rat where only a single AKR with positional- and stereo-specificity for 3alpha-hydroxysteroids exists. << Less
Biochem. J. 351:67-77(2000) [PubMed] [EuropePMC]
This publication is cited by 15 other entries.
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Expression cloning and characterization of human 17 beta-hydroxysteroid dehydrogenase type 2, a microsomal enzyme possessing 20 alpha-hydroxysteroid dehydrogenase activity.
Wu L., Einstein M., Geissler W.M., Chan H.K., Elliston K.O., Andersson S.
17 beta-Hydroxysteroid dehydrogenase (17 beta-HSD) is an enzyme crucial to the regulation of intracellular levels of biologically active steroid hormones in a variety of tissues. Here, we report the isolation, structure, and characterization of a cDNA encoding the human 17 beta-HSD type 2. A 1.4-k ... >> More
17 beta-Hydroxysteroid dehydrogenase (17 beta-HSD) is an enzyme crucial to the regulation of intracellular levels of biologically active steroid hormones in a variety of tissues. Here, we report the isolation, structure, and characterization of a cDNA encoding the human 17 beta-HSD type 2. A 1.4-kilobase cDNA was identified, and DNA sequence analysis indicated that 17 beta-HSD type 2 was a protein of 387 amino acids with a predicted molecular weight of 42,782. The protein contained an amino-terminal type II signal-anchor motif and a carboxyl-terminal endoplasmic reticulum retention motif, which suggested that 17 beta-HSD type 2 was associated with the membranes of the endoplasmic reticulum. 17 beta-HSD type 2 was capable of catalyzing the interconversion of testosterone and androstenedione as well as estradiol and estrone. The enzyme also demonstrated 20 alpha-HSD activity toward 20 alpha-dihydroprogesterone. The amount of 17 beta-HSD type 2 mRNA in placenta was found to be high. The data suggest that the 17 beta-HSD type 2 cDNA encodes the microsomal 17 beta-HSD of human placenta, described by several laboratories. << Less
J. Biol. Chem. 268:12964-12969(1993) [PubMed] [EuropePMC]
This publication is cited by 2 other entries.