Identification of a functionally impaired allele of human novel oxidoreductase 1 (NDOR1), NDOR1*1

Pharmacogenet Genomics. 2005 Jun;15(6):381-6. doi: 10.1097/01213011-200506000-00002.

Abstract

Objectives: Human novel oxidoreductase 1 (NDOR1) is a diflavin reductase closely related to cytochrome P450 reductase (POR) and nitric oxide synthase (NOS), which are involved in the metabolism of antitumour agents. A variant cDNA sequence of NDOR1, NDOR1 p.518-519ins9 or NDOR1_v1, has been deposited in GenBank (accession no. AK026089 and AY077845) that encodes an additional nine amino acids, which led us to investigate NDOR1 polymorphism.

Methods and results: We analysed genomic DNA from 200 Caucasian and 49 Japanese individuals by PCR--restriction fragment length polymorphism analysis. The nine amino acid residue sequence was found to be present in all individuals, encoded by a 27 nt intronic nucleotide sequence at an intron/exon junction, suggesting that this variant did not represent a common genetic polymorphism, but may have arisen from an alternative mRNA splicing event. However, further analysis of NDOR1 revealed a polymorphic c.1564G>A transition (NDOR1*1), detected in 24/200 Caucasian and 1/49 Japanese individuals, producing a valine to isoleucine substitution at codon 522 in the NADPH binding region. Expression of the flavin adenine dinucleotide/reduced nicotinamide phosphate dehydrogenase (NADPH) domain in Escherichia coli showed a significant 74% reduction in potassium ferricyanide reductase activity, but no effect on NADPH binding. NDOR1_v1 showed a 10-fold decrease in affinity for NADPH, and a 90% reduction in ferricyanide reductase activity.

Conclusions: We have discovered a polymorphic variant of NDOR1, NDOR1*1, that produces a functionally impaired enzyme. This will help define the structure and function of NDOR1 and its relationship to cancer and other diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles*
  • Amino Acid Sequence
  • Base Sequence
  • DNA
  • Electrophoresis, Polyacrylamide Gel
  • Flavoproteins / chemistry
  • Flavoproteins / genetics*
  • Humans
  • Molecular Sequence Data
  • Oxidoreductases / chemistry
  • Oxidoreductases / genetics*
  • Polymerase Chain Reaction
  • Polymorphism, Restriction Fragment Length
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Sequence Homology, Amino Acid

Substances

  • Flavoproteins
  • Recombinant Proteins
  • DNA
  • NDOR1 protein, human
  • Oxidoreductases

Associated data

  • GENBANK/AK026089
  • GENBANK/AY077845