Cloning and characterization of a pyridoxine 5'-phosphate oxidase from silkworm, Bombyx mori |
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| Authors: | S-H. Huang&dagger ,R-J. Shi&Dagger ,J-Y. Zhang&Dagger ,Z. Wang, L-Q. Huang |
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| Affiliation: | Key Laboratory of Tea Biochemistry &Biotechnology of Ministry of Education and Ministry of Agriculture, Anhui Agricultural University, Hefei, People's Republic of China;;Graduate School of Systems Life Sciences, Kyushu University, Fukuoka, Japan;and;College of Life Science, Anhui Agricultural University, Hefei, People's Republic of China |
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| Abstract: | 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. |
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| Keywords: | Bombyx mori pyridoxine 5'-phosphate oxidase cDNA cloning expression characterization |
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