Acid phosphatase/phosphotransferases from enteric bacteria
2001
Mihara, Y. (Ajinomoto Co. Inc., Kawasaki, Kanagawa (Japan). Central Research Labs.) | Utagawa, T. | Yamada, H. | Asano, Y.
We have investigated tbe enzymatic phosphorylation of nucleosides and found that Morganella morganii phoC acid phosphatase exhibits regioselective pyrophosphate (PPi)-nucleoside phosphotransferase activity. In this study, we isolated genes encoding an acid phosphatase with regioselective phosphotransferase activity (AP / PTase) from Providencia stuartii, Enterobacter aerogenes, Escherichia blattae and Klebsiella planticola, and compared the primary structures and enzymatic characteristics of these enzymes with those of AP/PTase (PhoC acid phosphatase) from M. morganii. The enzymes were highly homologous in primary structure with M. morganii AP / PTase, and are classified as class A1 acid phosphatases. The synthesis of inosine-5'-monophosphate (5'-IMP) by E. coli overproducing each acid phosphatase was investigated. The P. stuartii enzyme, which is most closely related to the M. morganii enzyme, exhibited high 5'-IMP productivity, similar to the M. morganii enzyme. The 5'-IMP productivities of the E. aerogenes, E. blattae and K. planticola enzymes were inferior to those of the former two enzymes. This result underlines the importance of lower K sub(m) values for efficient nucleotide production. As these enzymes exhibited a very high degree of homology at the amino acid sequence level, it is likely that local sequence differences in the binding pocket are responsible for the differences in the nucleosides-PPi Phosphotransferase reaction.
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