A water molecule in the stereospecificity pocket of Candida antarctica lipase B enhances enantioselectivity towards pentan-2-ol
2007 (English)In: ChemBioChem (Print), ISSN 1439-4227, E-ISSN 1439-7633, Vol. 8, no 6, 662-667 p.Article in journal (Refereed) Published
The effect of water activity on enzyme-catalyzed enantioselective transesterification was studied by using a solid/gas reactor. The experimental results were compared with predictions from molecular modelling. The system studied was the esterification of pentan-2-ol with methylpropanoate as acyl donor and lipase B from Candida antarctica as catalyst. The data showed a pronounced water-activity effect on both reaction rote and enantioselectivity. The enantioselectivity increased from 100, at water activity close to zero, to a maximum of 320, at a water activity of 0.2. Molecular modelling revealed how a water molecule could bind in the active site and obstruct the binding of the slowly reacting enantiomer. Measurements of enantioselectivity at different water-activity values and temperatures showed that the water molecule had a high affinity for the stereospecificity pocket of the active site with a binding energy of 9 kJ mol(-1), and that it lost all its degrees of rotation, corresponding to an entropic energy of 37 Jmol(-1)K(-1).
Place, publisher, year, edition, pages
2007. Vol. 8, no 6, 662-667 p.
enantioselectivity, enzyme catalysis, hydrolases, thermodynamics, water
IdentifiersURN: urn:nbn:se:kth:diva-14180DOI: 10.1002/cbic.200600479ISI: 000245907100015ScopusID: 2-s2.0-34250309643OAI: oai:DiVA.org:kth-14180DiVA: diva2:331468
QC 201007222010-07-222010-07-222010-07-22Bibliographically approved