Cloning and characterization of a pyridoxine 5'-phosphate oxidase from silkworm, Bombyx mori

Insect Mol Biol. 2009 Jun;18(3):365-71. doi: 10.1111/j.1365-2583.2009.00880.x.


A cDNA encoding Pyridoxine 5'-phosphate oxidase (PNPO) from Bombyx mori was cloned and characterized (GenBank accession number: DQ452398). The cDNA encodes a polypeptide of 257 amino acid residues. The recombinant enzyme purified from Escherichia coli exhibited maximal activity at pH 9.0, and the K(m) values for the substrates of pyridoxine 5'-phosphate and pyridoxamine 5'-phosphate were determined as 0.65 and 1.15 micromol/l. It was found that B. mori PNPO shares 51.44% homology with humans, but several function-related, key amino acid residues in B. mori PNPO are different from the human and E. Coli gene. B. mori has a single copy of the PNPO gene, which spans a 3.5 kb region and contains five exons and four introns. B. mori PNPO is a homodimer, with each monomer containing nine antiparallel beta-strands and five alpha-helical segments. The secondary structure was deduced from computational study.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bombyx / enzymology*
  • Bombyx / genetics
  • Cattle
  • Escherichia coli / metabolism
  • Genome, Insect
  • Humans
  • Mice
  • Protein Structure, Tertiary
  • Pyridoxaminephosphate Oxidase / chemistry
  • Pyridoxaminephosphate Oxidase / genetics
  • Pyridoxaminephosphate Oxidase / isolation & purification
  • Pyridoxaminephosphate Oxidase / metabolism*
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid


  • Recombinant Proteins
  • Pyridoxaminephosphate Oxidase