Enzymatic characteristics of retinal dehydrogenase type I expressed in Escherichia coli

Peter Penzes, Xianshu Wang, Joseph L. Napoli*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


We expressed RalDH(I) in Escherichia coli and have shown that it functions in vitro with the complex CRBP-retinal (cellular retinol-binding protein) as substrate, either generated in situ from the complex of CRBP-retinol and microsomal retinol dehydrogenases or provided directly as CRBP-retinal. Recombinant RalDH(I) had kinetic constants with CRBP-retinal of: Hill coefficient 1.8; K0.5 0.8 μM; and V(m) 1.5 nmol/min/mg of protein at 25°C. Apo-CRBP inhibited the reaction with CRBP-rerinal with an IC50 of 1.4 μM. Citral inhibited RalDH(I) with an IC50 of ~ 1 μM compared to an IC50 of ~ 12 for RalDH(II), but did not serve as substrate for RalDH(I). RalDH(I) did not catalyze efficiently the dehydrogenation of acetaldehyde, but showed higher V(max)/K(m) values for hexanal, octanal, decanal and benzaldehyde than for either propanal or retinal. These data extend the characterization of RalDH(I), show that apo-CRBP competes with holo-CRBP as substrate for RalDH(I), and expand insight into the pathways of retinoic acid biogenesis from the most abundant substratcs in vivo, retinoid-liganded CRBP.

Original languageEnglish (US)
Pages (from-to)175-181
Number of pages7
JournalBiochimica et Biophysica Acta - Protein Structure and Molecular Enzymology
Issue number2
StatePublished - Oct 17 1997


  • Aldehyde dehydrogenase
  • Retinal
  • Retinal dehydrogenase
  • Retinoic acid
  • Retinol

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology

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