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Cloning and characterization of a pyridoxine 5′‐phosphate oxidase from silkworm, Bombyx mori
Author(s) -
Huang SH.,
Shi RJ.,
Zhang JY.,
Wang Z.,
Huang LQ.
Publication year - 2009
Publication title -
insect molecular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.955
H-Index - 93
eISSN - 1365-2583
pISSN - 0962-1075
DOI - 10.1111/j.1365-2583.2009.00880.x
Subject(s) - bombyx mori , complementary dna , biochemistry , microbiology and biotechnology , bombyx , biology , pyridoxal , pyridoxal phosphate , escherichia coli , oxidase test , homology (biology) , peptide sequence , amino acid , gene , phosphate , enzyme , cofactor
A cDNA encoding Pyridoxine 5′‐phosphate oxidase (PNPO) from Bombyx mori was cloned and characterized (G en B ank 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 µmol/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 β‐strands and five α‐helical segments. The secondary structure was deduced from computational study.