Lipase catalyzed synthesis of l-alanyl, l-leucyl and l-phenylalanyl esters of d-glucose using unprotected amino acids

Abstract

Enzymatic synthesis of l-alanyl, l-leucyl and l-phenylalanyl esters of D-glucose was carried out in a non-polar solvent using lipases from Rhizomucor miehei and porcine pancreas. The unprotected amino acids at millimolar concentrations were used in presence of 10 to 50% (w/w) glucose of the lipases to give ester yields up to >99%. The reaction mixture on analysis by 2-D NMR showed that the product is a mixture of 6-O-, 3-O- and 2-O-monoesters and 2,6-di-O- and 3,6- di-O-esters.

Enzyme‐catalyzed regioselective synthesis of sugar esters and related compounds

“…The regioselective acylation of the rare sugar, D ‐allose (the C‐3 epimer of D ‐glucose) with fatty acid vinyl esters was successfully carried using Candida antarctica lipase in acetonitrile as solvent to give D ‐altose‐6‐alkanoates 52. During enzymatic esterification of D ‐glucose with amino acids using Rhizomucor miehei and Porcine pancreatic lipase, buffer salts gave higher yields 53, 54…”

Competitive inhibition by substrates of the esterification reaction between l-phenylalanine and d-glucose catalysed by the lipases of Rhizomucor miehei and Candida rugosa

“…Kinetic experiments were conducted by refluxing L-phenylalanine and D-glucose along with 90 mg RML/ CRL in 100 ml of a dichloromethane/dimethylformamide (90:10, v/v) solvent mixture containing 0.2 ml of 0.1 M acetate (pH 4.0) buffer (Vijayakumar et al 2004;Lohith and Divakar 2005) at 40°C. Unprotected and unactivated L-phenylalanine and D-glucose were employed (Sch.…”

Angiotensin converting enzyme inhibitory activity of amino acid esters of carbohydrates

“…The enzyme was imparted with 'pH memory' by employing: 0.1 mL Na 2 HPO 4 buffer (0.1 mM, pH 7.0) for l-valyl-d-glucose, 0.1 mL CH 3 COONa buffer (0.1 mM, pH 4.0) for l-alanyld-glucose, 0.2 mL CH 3 COONa buffer (0.2 mM, pH 4.0) for l-phenylalanyl-d-glucose and l-phenylalanyl-lactose. To facilitate complete removal of water from the reaction mixture, a very low water activity of a w = 0.0054 was achieved by condensing azeotropic solvent vapor containing small amount of water of reaction into a desiccant which was then drained back into the reaction mixture [14][15][16][17]. The same reactions were carried out in the absence of lipase, which did not show any esterification.…”

“…After completion of the reaction, the solvent was distilled off and then stirred with 20 mL of water and filtered to remove the lipase. The filtrate containing unreacted substrates and product esters was evaporated to dryness on a water bath and analyzed by HPLC employing a C-18 column or an aminopropyl column [14,17]. Conversion yields were determined from HPLC peak areas of the ester and l-amino acid and expressed as percentage esterification with respect to the l-amino acid concentration.…”