Enzymatic production of 5'-inosinic acid by a newly synthesised acid phosphatase/phosphotransferase.

Zhi-Qiang Liu, Ling Zhang, Li-Hui Sun, Xiao-Jun Li, Nan-Wei Wan, Yu-Guo Zheng

Institute of Bioengineering, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China.

Food chemistry 2012 Sep 15

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5'-Nucleotides including 5'-inosinic acid have characteristic taste and important application in various foods as flavour potentiators. The selective nucleoside acid phosphatase/phosphotransferase (AP/PTase) can catalyse the synthesis of 5'-nucleotides by transfer of phosphate groups. In this study, a 747-bp gene encoding AP/PTase from Escherichia blattae was synthesised. After expression, the recombinant AP/PTase was purified using nickel-NTA. The optimal temperature and pH of this enzyme were 30°C and 5.0, respectively. The activity was partially inhibited by metal ions such as Hg(2+), Ag(+) and Cu(2+), but not by chelating reagents such as EDTA. The values of K(m) and V(max) for inosine were 40 mM and 3.5 U/mg, respectively. Using this purified enzyme, 16.83 mM of 5'-IMP was synthesised from 37 mM of inosine and the molar yield reached 45.5%. Homology modelling and docking simulation were discussed. Copyright © 2012 Elsevier Ltd. All rights reserved.

Citation

Zhi-Qiang Liu, Ling Zhang, Li-Hui Sun, Xiao-Jun Li, Nan-Wei Wan, Yu-Guo Zheng. Enzymatic production of 5'-inosinic acid by a newly synthesised acid phosphatase/phosphotransferase. Food chemistry. 2012 Sep 15;134(2):948-56