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Improved Catalytic Performance of Bacillus megaterium Epoxide Hydrolase in a Medium Containing Tween‐80
Author(s) -
Gong PengFei,
Xu JianHe,
Tang YanFa,
Wu HuiYuan
Publication year - 2003
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp020293v
Subject(s) - epoxide hydrolase , bacillus megaterium , chemistry , epoxide , hydrolysis , substrate (aquarium) , enzyme , enantiomeric excess , hydrolase , catalysis , enantiomer , enantioselective synthesis , emulsion , stereochemistry , chromatography , organic chemistry , biology , bacteria , genetics , microsome , oceanography , geology
A new epoxide hydrolase with high enantioselectivity toward ( R )‐glycidyl phenyl ether ( R ‐GPE) was partially purified from Bacillus megaterium strain ECU1001. The maximum activity of the isolated enzyme was observed at 30 °C and pH 6.5 in a buffer system with 5% (v/v) of DMSO as a cosolvent. The enzyme was quite stable at pH 7.5 and retained full activity after incubation at 40 °C for 6 h. Interestingly, when the cosolvent DMSO was replaced by an emulsifier (Tween‐80, 0.5% w/v) as an alternative additive to help disperse the water‐insoluble substrate, the apparent activity of the epoxide hydrolase significantly increased by about 1.8‐fold, while the temperature optimum shifted from 30 to 40 °C and the half‐life of the enzyme at 50 °C increased by 2.5 times. The enzymatic hydrolysis of rac ‐GPE was highly enantioselective, with an E ‐value (enantiomeric ratio) of 69.3 in the Tween‐80 emulsion system, which is obviously higher than that (41.2) observed in the DMSO‐containing system.