title: Enzymatic production of 5'-inosinic acid by a newly synthesised acid phosphatase/phosphotransferase.
abstract: 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.
authors.affiliation: Institute of Bioengineering, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China.
authors.forename: Zhi-Qiang
authors.initials: ZQ
authors.lastname: Liu
authors.forename: Ling
authors.initials: L
authors.lastname: Zhang
authors.forename: Li-Hui
authors.initials: LH
authors.lastname: Sun
authors.forename: Xiao-Jun
authors.initials: XJ
authors.lastname: Li
authors.forename: Nan-Wei
authors.initials: NW
authors.lastname: Wan
authors.forename: Yu-Guo
authors.initials: YG
authors.lastname: Zheng
mesh_terms: D000135:Acid Phosphatase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004795:Enzyme Stability; D004925:Escherichia / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D007291:Inosine Monophosphate / Q000378:metabolism*; D007700:Kinetics; D010770:Phosphotransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D007291:Inosine Monophosphate; D010770:Phosphotransferases; D000135:Acid Phosphatase