INTECIN   20395
INSTITUTO DE TECNOLOGIAS Y CIENCIAS DE LA INGENIERIA "HILARIO FERNANDEZ LONG"
Unidad Ejecutora - UE
artículos
Título:
Molecular Modeling of the Mechanism of Ethyl Fatty Ester Synthesis Catalyzed by Lipases. Effects of Structural Water and Ethanol initial Co-adsorption with the Fatty acid
Autor/es:
M.L. FORESTI; M.L. FERREIRA
Revista:
JOURNAL OF MOLECULAR CATALYSIS B-ENZYMATIC
Editorial:
Elsevier
Referencias:
Año: 2009 vol. 61 p. 289 - 295
ISSN:
1381-1177
Resumen:
This manuscript presents an MM2 modeling of the esterification of model fatty acids (oleic acid and 9-decenoic acid) with ethanol using lipases from Candida antarctica B (CALB) and Candida rugosa (CRL). The role of water and ethanol as part of an H-bonding network acting at the adsorption of the fatty acid, the stabilization of intermediaries and the acyl enzyme and on the regeneration of the Serine OH are taken into account. The model includes the consideration of the tunnel and the catalytic triad/oxyanion hole- the large active site- for CRL and CALB-using structures of the open lipases from the PDB.Besides, an additional molecular modeling of the H- bonding distances found in the intermediaries and the acyl enzyme using CALB was carried out. The fatty acid esterification demonstrated to be activated for CRL and almost non-activated for CALB- in the context of the large active sites. When the results of the additional MM2 modeling (for a shorter model) were analyzed. H-bonding at the level of the strong and weak H- bonding between Histidine, water, ethanol and O from Serine were found. Molecular modeling results also revealed that the presence of a molecule of water at the catalytic triad of both lipases promotes a significant change in the calculated energy profiles to lower energies and a potential too strong adsorption of substrates and products.There is qualitative agreement between the theoretical modeling and the experimental work published elsewhere.