Activity and selectivity of some hydrolases in enantiomeric solvents

Abstract

The activity and the regio-and enantioselectivity of five lipases and one protease were investigated in the two enanfiomeric solvents (R)-carvone and (S)-carvone. It was found that in all cases enzyme activity changed as a function of solvent configuration and that, for the same enzyme, it was higher in (R)-carvone or in (S)-carvone depending on the nature of the substrate. Instead, no significative variation of regio-and enantioselectivity was observed moving from one enantiomeric solvent to the other.

Study on the enzymatic polymerization mechanism of lactone and the strategy for improving the degree of polymerization

“…The observed differences cannot be explained simply by log P; other physicochemical properties should also be considered. For instance, reports of solvent-induced reversal of activity and stereoselectivity of enzymes 39,41,42 led us to suspect that solvent geometry may affect enzymatic polymerization. In addition, the sol- vent's dipole moment might also contribute.…”

Overexpression and properties of a new thermophilic and thermostable esterase from Bacillus acidocaldarius with sequence similarity to hormone-sensitive lipase subfamily

“…The substrate (20 mg) was dissolved in 2 ml of toluene containing 5 % (v\v) vinyl acetate and 150 µg of enzyme (adsorbed on 100 mg of Celite), pre-equilibrated at a water activity value of 0.85 [33]. The reaction mixture was shaken at room temperature for a scheduled time and then analysed for conversion and enantiomeric excess of the products.…”

“…Both the degree of conversion and the enantiomeric excess of the products were determined by chiral GLC for 1, 2, 5, 6 and 7 [33][34][35] or chiral HPLC for 3 and 4 [35,36]. The enantioselectivity of the enzyme was expressed as the enantiomeric ratio, E, which was obtained from the equation E l ln[1kc(1je P )]\ ln[1kc(1ke P )], where c is the degree of conversion and e P the enantiomeric excess of the product [37].…”

“…The results obtained in the esterase-catalysed resolution of several racemic alcohols of interest in the pharmaceutical or pheromone field [33][34][35][36] are summarized in Table 3. The enzyme was very effective as a catalyst ; significant conversions were achieved in short reaction periods and with high substrate-to-enzyme ratios.…”

Construcción de CLEAs de lipasas: evaluación del efecto y modulación de la enantioselectividad

“…Gracias a la cristalografía de rayos X, pudieron identificar las moléculas de solventes como hexano y acetonitrilo unidas al sitio activo de una proteasa. Incluso solventes enantioméricos como la (S) y (R)-carbona modifican en un factor de hasta 8 veces la enantioselectividad de algunas lipasas como las CRL, RML y PSL (Ottolina et al, 1994).…”