FACTORS AFFECTING THE LIPASE-CATALYZED TRANSESTERIFICATION REACTIONS OF 3-HYDROXY ESTERS IN ORGANIC-SOLVENTS

BORNSCHEUER, U; HERAR, A; KREYE, L; WENDEL, V; CAPEWELL, A; MEYER, HH; SCHEPER, T; KOLISIS, FN

dc.contributor.author	BORNSCHEUER, U	en
dc.contributor.author	HERAR, A	en
dc.contributor.author	KREYE, L	en
dc.contributor.author	WENDEL, V	en
dc.contributor.author	CAPEWELL, A	en
dc.contributor.author	MEYER, HH	en
dc.contributor.author	SCHEPER, T	en
dc.contributor.author	KOLISIS, FN	en
dc.date.accessioned	2014-03-01T01:42:06Z
dc.date.available	2014-03-01T01:42:06Z
dc.date.issued	1993	en
dc.identifier.issn	0957-4166	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/23704
dc.subject.classification	Chemistry, Inorganic & Nuclear	en
dc.subject.classification	Chemistry, Organic	en
dc.subject.classification	Chemistry, Physical	en
dc.subject.other	ENZYME ENANTIOSELECTIVITY	en
dc.subject.other	WATER ACTIVITY	en
dc.subject.other	MEDIA	en
dc.subject.other	RESOLUTION	en
dc.title	FACTORS AFFECTING THE LIPASE-CATALYZED TRANSESTERIFICATION REACTIONS OF 3-HYDROXY ESTERS IN ORGANIC-SOLVENTS	en
heal.type	journalArticle	en
heal.language	English	en
heal.publicationDate	1993	en
heal.abstract	Chiral resolutions of racemic 3-hydroxy esters were performed in organic phases with lipases from Pseudomonas cepacia, Chromobacterium viscosum and Porcine pancreas. The reaction conditions have been optimized with 3-hydroxy octanoic acid methyl ester. Different organic solvents have been tested showing a tendentious correlation with the hydrophobicity of the solvents expressed as log P. The reaction time was shortened six fold by using irreversible acylating agents. We have found solvent type, lipase type and acylating agent acting as tools for changing the enantioselectivity. Lipase from Pseudomonas cepacia was lyophilized at different pH and the influence of the amount of water added was investigated, resulting in the highest activity at the pH optimum and a denaturation of the lipase above 1 % water (w/w(lipase). The water activity was measured on-line with a humidity sensor. Water activities greater than 0.4 led to a decrease in enantioselectivity and reaction rate. In the optimized system the resolutions of other 3-hydroxy esters were tested. Aliphatic compounds reacted with lower enantioselectivity, only the substrates could be isolated in high enantiomeric purity. In contrast, aromatic 3-hydroxy esters were acylated by lipases with high stereoselectivity. A model of the active site of lipase from Pseudomonas sp. explained these experimental observations.	en
heal.publisher	PERGAMON-ELSEVIER SCIENCE LTD	en
heal.journalName	TETRAHEDRON-ASYMMETRY	en
dc.identifier.isi	ISI:A1993LE56000036	en
dc.identifier.volume	4	en
dc.identifier.issue	5	en
dc.identifier.spage	1007	en
dc.identifier.epage	1016	en