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Structure and properties of recombinant human pyridoxine 5′‐phosphate oxidase
Author(s) -
Musayev Faik N.,
Di Salvo Martino L.,
Ko TzuPing,
Schirch Verne,
Safo Martin K.
Publication year - 2003
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.0356203
Subject(s) - biochemistry , pyridoxamine , enzyme , pyridoxine , pyridoxal , escherichia coli , pyridoxal phosphate , chemistry , phosphate , cofactor , gene
Pyridoxine 5′‐phosphate oxidase catalyzes the terminal step in the synthesis of pyridoxal 5′‐phosphate. The cDNA for the human enzyme has been cloned and expressed in Escherichia coli . The purified human enzyme is a homodimer that exhibits a low catalytic rate constant of ∼0.2 sec −1 and K m values in the low micromolar range for both pyridoxine 5′phosphate and pyridoxamine 5′‐phosphate. Pyridoxal 5′‐phosphate is an effective product inhibitor. The three‐dimensional fold of the human enzyme is very similar to those of the E. coli and yeast enzymes. The human and E. coli enzymes share 39% sequence identity, but the binding sites for the tightly bound FMN and substrate are highly conserved. As observed with the E. coli enzyme, the human enzyme binds one molecule of pyridoxal 5′‐phosphate tightly on each subunit.