1.Opposite effects of D-glucose pentaacetate and D-galactose pentaacetate anomers on insulin release evoked by succinic acid dimethyl ester in rat pancreatic islets.
Kadiata MM1, Malaisse WJ. Life Sci. 1999;64(9):751-4.
Both alpha- and beta-D-glucose pentaacetate (1.7 mM each) augmented, to almost the same extent, insulin release caused by succinic acid dimethyl ester (10.0 mM) in rat pancreatic islets. The secretory response to these hexose esters largely exceeded that evoked by unesterified D-glucose tested at the same concentration (1.7 mM). The release of insulin provoked by succinic acid dimethyl ester was inhibited, however, by alpha-D-galactose pentaacetate, whilst being unaffected by beta-D-galactose pentaacetate (each also 1.7 mM). It appears, therefore, that the insulinotropic action of hexose esters is not attributable solely to the catabolism of their carbohydrate moiety, but may also involve a receptor system that displays anomeric specificity and can be directly activated or inhibited by the esters themselves. Hence, it is proposed that selected esters of non-nutrient monosaccharides may represent new tools to either stimulate insulin release in diabetes or prevent excessive hormonal secretion in situations of hyperinsulinemia.
2.Preparation of various glucose esters via lipase-catalyzed hydrolysis of glucose pentaacetate.
Shaw JF1, Klibanov AM. Biotechnol Bioeng. 1987 Apr;29(5):648-51.
Beta-D(+)-glucose pentaacetate was hydrolyzed both chemically and enzymatically. In contrast to the alkaline hydrolysis, esterase-catalyzed deacetylations afforded significant accumulation of intermediate glucose esters at different degrees of substrate conversion. Aspergillus niger lipase, the most suitable of the four enzymes tested, was used for preparative hydrolysis of glucose pentaacetate. As a result, gram quantities of pure glucose-2,3,4,6-tetraacetate, glucose triacetate (a mixture of two positional isomers, 2,4,6- and 3,4,6-), and glucose-4,6-diacetate were prepared.
3.Insulinotropic action of alpha-D-glucose pentaacetate: functional aspects.
Malaisse WJ1, Sánchez-Soto C, Larrieta ME, Hiriart M, Jijakli H, Viñambres C, Villanueva-Peñacarrillo ML, Valverde I, Kirk O, Kadiata MM, Sener A. Am J Physiol. 1997 Dec;273(6 Pt 1):E1090-101.
The functional determinants of the insulinotropic action of alpha-D-glucose pentaacetate were investigated in rat pancreatic islets. The ester mimicked the effect of nutrient secretagogues by recruiting individual B cells into an active secretory state, stimulating proinsulin biosynthesis, inhibiting 86Rb outflow, and augmenting 45Ca efflux from prelabeled islets. The secretory response to the ester was suppressed in the absence of Ca2+ and potentiated by theophylline or cytochalasin B. The generation of acetate from the ester apparently played a small role in its insulinotropic action. Thus acetate, methyl acetate, ethyl acetate, alpha-D-galactose pentaacetate, and beta-D-galactose pentaacetate all failed to stimulate insulin release. The secretory response to alpha-D-glucose pentaacetate was reproduced by beta-D-glucose pentaacetate and, to a lesser extent, by beta-L-glucose pentaacetate. It differed from that evoked by unesterified D-glucose by its resistance to 3-O-methyl-D-glucose, D-mannoheptulose, and 2-deoxy-D-glucose.
4.A simple preparation of 2,3,4,6-tetra-o-acyl-gluco-, galacto- and mannopyranoses and relevant theoretical study.
Wang ZD1, Mo Y, Chiou CL, Liu M. Molecules. 2010 Jan 18;15(1):374-84. doi: 10.3390/molecules15010374.
The deacylation of glucose, galactose and mannose pentaacetates, galactose and mannose penta(3-bromo)benzoates, as well as the dealkylation of 2,3,4,6-tetra-O-acetyl and 2,3,4,6-tetra-O-(3-bromo)benzoyl methyl alpha-D-glucopyranosides have been studied. In addition, a computational study on the deacylation of beta-D-glucose pentaacetate has been carried out with density functional theory (B3LYP/6-31G*). The anomeric effect during deacetylation and dealkylation has been clearly demonstrated in both experimental and computational results.
