Rabbit dehydrogenase/reductase SDR family member 11 (DHRS11): Its identity with acetohexamide reductase with broad substrate specificity and inhibitor sensitivity, different from human DHRS11

Chem Biol Interact. 2019 May 25:305:12-20. doi: 10.1016/j.cbi.2019.03.026. Epub 2019 Mar 26.

Abstract

Human dehydrogenase/reductase SDR family member 11 (DHRS11) has been recently reported to be an NADP+-dependent 3(17)β-hydroxysteroid dehydrogenase, and its orthologs are predicted in genomic analyses of various animals. Among them, the amino acid sequence of predicted rabbit DHRS11 shares 92% identity with that of human DHRS11 and matches peptide sequences (composed of total 87 amino acids) of rabbit heart acetohexamide reductase (RHAR) previously reported. However, the physiological role of RHAR remains unknown, because its known substrates are only acetohexamide and 1,4-naphthoquinone. To elucidate whether the two rabbit enzymes are identical, we have isolated the cDNA for rabbit DHRS11, which was abundantly detected in the brain, heart, kidney and intestine by RT-PCR. The recombinant rabbit DHRS11 reduced acetohexamide and 1,4-naphthoquinone, and was inhibited by tolbutamide and phenobarbital (RHAR-specific inhibitors), demonstrating its identity with RHAR. Rabbit DHRS11 also reduced α-dicarbonyl compounds, aldehydes and aromatic ketones (acetylbenzenes and acetylpyridines), and exhibited 3(17)β-hydroxysteroid dehydrogenase activity. It was competitively inhibited not only by tolbutamide and phenobarbital, but also more potently by several non-steroidal anti-inflammatory drugs such as diclofenac and sulindac. The broad substrate specificity and inhibitor sensitivity were different from those of human DHRS11, which did not reduce aliphatic aldehydes and aromatic ketones despite its higher 3(17)β-hydroxysteroid dehydrogenase activity, and was insensitive to tolbutamide, phenobarbital and diclofenac. The site-directed mutagenesis of Thr163 and Val200 in human DHRS11 to the corresponding residues (Gly and Leu, respectively) in rabbit DHRS11 suggested that these residues are pertinent to the differences in properties of rabbit and human DHRS11s.

Keywords: 3(17)β-hydroxysteroid dehydrogenase; Acetohexamide; DHRS11; Phenobarbital; Rabbit; Substrate-binding residue.

MeSH terms

  • 17-Hydroxysteroid Dehydrogenases / antagonists & inhibitors
  • 17-Hydroxysteroid Dehydrogenases / genetics
  • 17-Hydroxysteroid Dehydrogenases / metabolism*
  • Acetohexamide / metabolism
  • Alcohol Oxidoreductases / antagonists & inhibitors
  • Alcohol Oxidoreductases / chemistry
  • Alcohol Oxidoreductases / metabolism*
  • Amino Acid Sequence
  • Animals
  • Catalytic Domain
  • Diclofenac / chemistry
  • Diclofenac / metabolism
  • Humans
  • Kinetics
  • Male
  • Mutagenesis
  • Myocardium / enzymology
  • Phenobarbital / chemistry
  • Phenobarbital / metabolism
  • Rabbits
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Sequence Alignment
  • Substrate Specificity
  • Tolbutamide / chemistry
  • Tolbutamide / metabolism

Substances

  • Recombinant Proteins
  • Diclofenac
  • Tolbutamide
  • 17-Hydroxysteroid Dehydrogenases
  • Alcohol Oxidoreductases
  • DHRS11 protein, human
  • acetohexamide reductase
  • Acetohexamide
  • Phenobarbital