ChemInform Abstract: Synthesis of Aryl 3-O-β-Cellobiosyl-β-D-glucopyranosides for Reactivity Studies of 1,3-1,4-β-Glucanases

Autor: Óscar Millet, Cristina Pallarés, Josep Palasi, Josep-Lluı́s Viladot, Antoni Planas, Mireia Abel
Rok vydání: 2010
Předmět:
Zdroj: ChemInform. 30
ISSN: 1522-2667
0931-7597
DOI: 10.1002/chin.199903195
Popis: A series of substituted aryl β -glycosides derived from 3- O - β -cellobiosyl- d -glucopyranose with different phenol-leaving group abilities as measured by the pK a of the free phenol group upon enzymatic hydrolysis has been synthesised. Aryl β -glycosides with a pK a of the free phenol leaving group>5 were prepared by phase-transfer glycosidation of the per- O -acetylated α -glycosyl bromide with the corresponding phenol, whereas the 2,4-dinitrophenyl β -glycoside was obtained by condensation of 1-fluoro-2,4-dinitrobenzene with the partially acetylated trisaccharide followed by acid de- O -acetylation. The aryl β -glycosides have been used for reactivity studies of the wild-type Bacillus licheniformis 1,3-1,4- β - d -glucan 4-glucanohydrolase. The Hammett plot log k cat versus pK a is biphasic with an upward curvature at low pK a values suggesting a change in transition-state structure depending on the aglycon.
Databáze: OpenAIRE
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