Lipase regio‐ and stereoselectivities toward three enantiomeric pairs of didecanoyl‐deoxyamino‐O methyl glycerol: A kinetic study by the monomolecular film technique

Abstract

A kinetic study was carried out on the regio- and stereoselectivities of 12 lipases of animal and microbial origin. For this purpose, monomolecular films consisting of three pairs of enantiomers (didecanoyl-deoxyamino-O methyl glycerol, DDG) containing a single hydrolyzable decanoyl ester bond and two lipase-resistant groups were spread at the air-water interface. Each of the lipases tested displayed a particular type of behavior, on the basis of which they were classified in two groups, depending on their ability to hydrolyze the sn-2 position. From the qualitative point of view, the sn-2 preference measured on triacylglycerides and DDG were in good agreement. The inductive chemical effect might explain why a greater level of hydrolytic activity was observed with the diglycerides than with DDG. With most of the lipases tested, it was observed that the enantiomeric pair having two distal acyl chains was more clearly differentiated stereochemically than the two homologous pairs with two adjacent acyl chains. This finding is consistent with the hypothesis that during the chiral recognition process two of the three attachment points may be the external (distal) hydrophobic chains, which is in line with the hypothesis of a tuning fork conformation of a triglyceride in the lipase active site.

Staphylococcal lipases stereoselectively hydrolyse the sn-2 position of monomolecular films of diglyceride analogs. Application to sn-2 hydrolysis of triolein

“…2). This finding is in agreement with data obtained by Douchet et al [34] using various microbial lipases. Based on the data presented in Figs.…”

“…In previous studies, Deveer et al [33] and Douchet et al [34] used six pure chiral synthetic pseudodiglycerides ( Fig. 1) containing a single hydrolysable decanoyl ester and two lipase-resistant groups (one decanoylamino and one methyl ether from the didecanoyl-deoxyamino-O-methyl glycerol, DDG).…”

“…These compounds were synthesised by de Haas' group in order to be able to assess the regio-and stereo-specificities of the lipase without having to worry about acyl chain migration problems. The lipases tested by Douchet et al [34] showed a particular type of behavior, on the basis of which they were classified into two groups, depending on whether or not they were able to hydrolyse the sn-2 position.…”

An ultraviolet spectrophotometric assay for the screening of sn-2-specific lipases using 1,3-O-dioleoyl-2-O-α-eleostearoyl-sn-glycerol as substrate

“…All the TLC experiments confi rmed the specifi cities of CALA, YLLIP2 and HPL ( 29,43,44 ). They show however, that MAGs with ␣ -eleostearic acid could be produced by HPL and to a lesser extent by YLLIP2.…”

“…CALA is known to display a stereopreference for the sn -2 position of TAGs ( 29,43 ). HPL and YLLIP2 are known to be 1,3-sn -regioselective lipases ( 4,29,44 ).…”