Purification and Characterization of Pyridoxal 4-Dehydrogenase from Aureobacterium luteolum
2002
TRONGPANICH, Yanee | ABE, Kinuyo | KANEDA, Yasuo | MORITA, Tomotake | YAGI, Toshiharu
A pyridoxal dehydrogenase was purified to homogeneity from Aureobacterium luteolum, which can use pyridoxine as a carbon and nitrogen source, and characterized. The enzyme was a dimeric protein with a subunit molecular weight of 38,000. It had several properties distinct from those of the partially purified enzyme from Pseudomonas MA-1. The optimum pH (8.0–8.5) was 0.8–1.3 lower than that of the Pseudomonas enzyme. The Aureobacterium enzyme showed much higher and lower affinities for NAD⁺ (Km, 0.140±0.008 mM) and pyridoxal (0.473±0.109 mM), respectively, than those of the Pseudomonas enzyme. The Aureobacterium enzyme could use NADP⁺ as a substrate: the reactivity was 6.5% of NAD⁺. The enzyme was much more tolerant to metal-chelating agents. Irreversibility of the enzymatic reaction was shared by the two enzymes. No aldehyde dehydrogenase showed similarity to the amino-terminal amino acid sequence of the enzyme.
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