Influence of water activity on the enantioselective esterification of (R,S)-ibuprofen by Candida antarctica lipase B in solventless media.
The lipase-catalyzed enantioselective esterification of ibuprofen has been studied in a media, composed only of substrates. When racemic ibuprofen is used, the alcohol-chain length affects the esterification rates of individual enantiomers, but it does not affect the enantioselectivity. Water activity affects the esterification rates of (R)- and (S)-ibuprofen differently, leading to higher enantioselectivity at lower water activities. Experiments were also conducted at various (R)- to (S)-ibuprofen ratios. It appears that the esterification rate of (R)-ibuprofen is always proportional to its concentration, whereas at low water activity the esterification rate of (S)-ibuprofen shows a saturation at higher concentrations. Other 2-phenyl carboxylic acids were studied, and the increase in apparent enantioselectivity at low-water activity was not observed for the molecules tested.
Pepin
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Microbial and Enzymatic Technology Group, Biotechnology Research Institute, National Research Council, 6100 Royalmount Avenue, Montreal (Qc), H4P 2R2, Canada.
Lortie
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D001711:Biotransformation; D002175:Candida / Q000201:enzymology*; D003470:Culture Media; D004952:Esters; D007052:Ibuprofen / Q000031:analogs & derivatives* / Q000493:pharmacokinetics*; D007700:Kinetics; D008049:Lipase / Q000378:metabolism*; D013237:Stereoisomerism; D013379:Substrate Specificity
D003470:Culture Media; D004952:Esters; D008049:Lipase; D007052:Ibuprofen