3-oxo-5-beta-steroid 4-dehydrogenase; delta(4)-3-ketosteroid 5-beta-reductase; delta(4)-3-oxosteroid 5-beta-reductase; aldo-keto reductase family 1 member D1 (AKR1D1, SRD5B1)

Function

• catalyzes reduction of progesterone, androstenedione, 17-alpha-hydroxyprogesterone & testosterone to 5-beta-reduced metabolites
• bile acid intermediates 7-alpha,12-alpha-dihydroxy-4-cholesten-3-one & 7-alpha-hydroxy-4-cholesten-3-one can also act as substrates subject to inhibition by high substrate concentrations
• inhibited by testosterone concentrations above 10 uM

Kinetic parameters:

• KM=2.7 uM for testosterone

5-beta-cholestan-3-one + NADP+ <--> cholest-4-en-3-one + NADPH

17,21-dihydroxy-5-beta-pregnane-3,11,20-trione + NADP+
           <-->
cortisone

Structure

belongs to the aldo/keto reductase family

Compartment

cytoplasm

Expression

• highly expressed in liver
• expressed in testis & weakly in colon

Pathology

• defects in AKR1D1 are the cause of congenital bile acid synthesis defect type 2

More general terms

• aldo-keto reductase

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=6718
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:6718
• OMIM: https://mirror.omim.org/entry/235555
• OMIM: https://mirror.omim.org/entry/604741
• UniProt: http://www.uniprot.org/uniprot/P51857.html