Publications

• Purification, molecular cloning, and catalytic activity of Schizosaccharomyces pombe pyridoxal reductase. A possible additional family in the aldo-keto reductase superfamily.

  Nakano M., Morita T., Yamamoto T., Sano H., Ashiuchi M., Masui R., Kuramitsu S., Yagi T.

  Pyridoxal reductase (PL reductase), which catalyzes reduction of PL by NADPH to form pyridoxine and NADP(+), was purified from Schizosaccharomyces pombe. The purified enzyme was very unstable but was stabilized by low concentrations of various detergents such as Tween 40. The enzyme was a monomeri ... >> More

  Pyridoxal reductase (PL reductase), which catalyzes reduction of PL by NADPH to form pyridoxine and NADP(+), was purified from Schizosaccharomyces pombe. The purified enzyme was very unstable but was stabilized by low concentrations of various detergents such as Tween 40. The enzyme was a monomeric protein with the native molecular weight of 41,000 +/-1,600. The enzyme showed a single absorption peak at 280 nm (E(1%) = 10.0). PL and 2-nitrobenzaldehyde were excellent substrates, and no measurable activity was observed with short chain aliphatic aldehydes; substrate specificity of PL reductase was obviously different from those of yeast aldo-keto reductases (AKRs) so far purified. The peptide sequences of PL reductase were identical with those in a hypothetical 333-amino acid protein from S. pombe (the DDBJ/EMBL/GenBank(TM) accession number D89205). The gene corresponding to this protein was expressed in Escherichia coli, and the purified protein was found to have PL reductase activity. The recombinant PL reductase showed the same properties as those of native PL reductase. PL reductase showed only low sequence identities with members of AKR superfamily established to date; it shows the highest identity (18.5%) with human Shaker-related voltage-gated K(+) channel beta2 subunit. The elements of secondary structure of PL reductase, however, distributed similarly to those demonstrated in the three-dimensional structure of human aldose reductase except that loop A region is lost, and loop B region is extended. Amino acid residues involved in substrate binding or catalysis are also conserved. Conservation of these features, together with the major modifications, establish PL reductase as the first member of a new AKR family, AKR8. << Less

  J. Biol. Chem. 274:23185-23190(1999) [PubMed] [EuropePMC]

• Identification and characterization of a pyridoxal reductase involved in the vitamin B6 salvage pathway in Arabidopsis.

  Herrero S., Gonzalez E., Gillikin J.W., Velez H., Daub M.E.

  Vitamin B6 (pyridoxal phosphate) is an essential cofactor in enzymatic reactions involved in numerous cellular processes and also plays a role in oxidative stress responses. In plants, the pathway for de novo synthesis of pyridoxal phosphate has been well characterized, however only two enzymes, p ... >> More

  Vitamin B6 (pyridoxal phosphate) is an essential cofactor in enzymatic reactions involved in numerous cellular processes and also plays a role in oxidative stress responses. In plants, the pathway for de novo synthesis of pyridoxal phosphate has been well characterized, however only two enzymes, pyridoxal (pyridoxine, pyridoxamine) kinase (SOS4) and pyridoxamine (pyridoxine) 5' phosphate oxidase (PDX3), have been identified in the salvage pathway that interconverts between the six vitamin B6 vitamers. A putative pyridoxal reductase (PLR1) was identified in Arabidopsis based on sequence homology with the protein in yeast. Cloning and expression of the AtPLR1 coding region in a yeast mutant deficient for pyridoxal reductase confirmed that the enzyme catalyzes the NADPH-mediated reduction of pyridoxal to pyridoxine. Two Arabidopsis T-DNA insertion mutant lines with insertions in the promoter sequences of AtPLR1 were established and characterized. Quantitative RT-PCR analysis of the plr1 mutants showed little change in expression of the vitamin B6 de novo pathway genes, but significant increases in expression of the known salvage pathway genes, PDX3 and SOS4. In addition, AtPLR1 was also upregulated in pdx3 and sos4 mutants. Analysis of vitamer levels by HPLC showed that both plr1 mutants had lower levels of total vitamin B6, with significantly decreased levels of pyridoxal, pyridoxal 5'-phosphate, pyridoxamine, and pyridoxamine 5'-phosphate. By contrast, there was no consistent significant change in pyridoxine and pyridoxine 5'-phosphate levels. The plr1 mutants had normal root growth, but were significantly smaller than wild type plants. When assayed for abiotic stress resistance, plr1 mutants did not differ from wild type in their response to chilling and high light, but showed greater inhibition when grown on NaCl or mannitol, suggesting a role in osmotic stress resistance. This is the first report of a pyridoxal reductase in the vitamin B6 salvage pathway in plants. << Less

  Plant Mol. Biol. 76:157-169(2011) [PubMed] [EuropePMC]

• Purification and properties of pyridoxine oxidase from Aureobacterium luteolum and pyridoxal reductase from Schizosaccharomyces pombe.

  Yagi T., Ashiuchi M., Kaneda Y., Sano H.

  BioFactors 11:123-126(2000) [PubMed] [EuropePMC]