Substrate Specificity, Inhibitor Selectivity and Structure-Function Relationships of Aldo-Keto Reductase 1B15: A Novel Human Retinaldehyde Reductase

PLoS One. 2015 Jul 29;10(7):e0134506. doi: 10.1371/journal.pone.0134506. eCollection 2015.


Human aldo-keto reductase 1B15 (AKR1B15) is a newly discovered enzyme which shares 92% amino acid sequence identity with AKR1B10. While AKR1B10 is a well characterized enzyme with high retinaldehyde reductase activity, involved in the development of several cancer types, the enzymatic activity and physiological role of AKR1B15 are still poorly known. Here, the purified recombinant enzyme has been subjected to substrate specificity characterization, kinetic analysis and inhibitor screening, combined with structural modeling. AKR1B15 is active towards a variety of carbonyl substrates, including retinoids, with lower kcat and Km values than AKR1B10. In contrast to AKR1B10, which strongly prefers all-trans-retinaldehyde, AKR1B15 exhibits superior catalytic efficiency with 9-cis-retinaldehyde, the best substrate found for this enzyme. With ketone and dicarbonyl substrates, AKR1B15 also shows higher catalytic activity than AKR1B10. Several typical AKR inhibitors do not significantly affect AKR1B15 activity. Amino acid substitutions clustered in loops A and C result in a smaller, more hydrophobic and more rigid active site in AKR1B15 compared with the AKR1B10 pocket, consistent with distinct substrate specificity and narrower inhibitor selectivity for AKR1B15.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aldehyde Reductase / antagonists & inhibitors
  • Aldehyde Reductase / genetics
  • Aldehyde Reductase / metabolism
  • Aldo-Keto Reductases
  • Amino Acid Sequence
  • Amino Acid Substitution
  • Catalytic Domain / genetics
  • Diterpenes
  • Enzyme Inhibitors / pharmacology
  • Humans
  • Kinetics
  • Models, Molecular
  • Oxidoreductases Acting on Aldehyde or Oxo Group Donors / antagonists & inhibitors
  • Oxidoreductases Acting on Aldehyde or Oxo Group Donors / genetics
  • Oxidoreductases Acting on Aldehyde or Oxo Group Donors / metabolism*
  • Protein Conformation
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Retinaldehyde / metabolism*
  • Structural Homology, Protein
  • Substrate Specificity


  • Diterpenes
  • Enzyme Inhibitors
  • Recombinant Proteins
  • 9-cis-retinal
  • AKR1B10 protein, human
  • AKR1B15 protein, human
  • Aldo-Keto Reductases
  • Aldehyde Reductase
  • Oxidoreductases Acting on Aldehyde or Oxo Group Donors
  • Retinaldehyde

Grants and funding

JGD, IC, XP, JF and SP received support from Spanish Ministerio de Economía y Competitividad [BFU2011-24176] ( and Generalitat de Catalunya [2009 SGR 795] ( FXR, ACS and AP received support from Centre National de la Récherche Scientifique (; Institut National de la Santé et de la Recherche Médicale (; Université de Strasbourg (; Région Alsace (; Hôpital Civil de Strasbourg (;l Instruct (part of the European Strategy Forum of Research Infrastructures; ESFRI) (; and French Infrastructure for Integrated Structural Biology (FRISBI) [ANR-10-INSB-05-01] ( FXR received support from Fondation pour la Recherche Médicale [SPF20121226275] ( The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.