Four orders of magnitude rate increase in artificial enzyme-catalyzed aryl glycoside hydrolysis

作者：Ortega Caballero F; Bjerre J; Laustsen LS; Bols M^*

来源：Journal of Organic Chemistry, 2005, 70(18): 7217-7226.

DOI：10.1021/jo050861w

(6(A)R,6(D)R)-6(A) 6(D)-Di-C-cyano-beta-cyclodextrin (1) and 6(A) 6(D)-di-C-cyano-alpha-cyclodextrin (2) were synthesized and shown to catalyze hydrolysis of aryl glycosides into glucose and phenol with a reaction following Michaelis-Menten kinetics. At pH 8.0 and 59 degrees C hydrolysis of 4-nitrophenyl alpha-glucopyranoside was catalyzed by I with Km = 10.5 +/- 1.5 mM, k(cat) = 1.42(+/- 0.09) x 10(-4) s(-1), and k(cat)/k(uncat) = 7922. Catalysis was observed with a concentration of 1 as low as 10 mu M. Hydrolysis of the other aryl glycosides containing stereochemical variation in the sugar-moiety and 4-nitro-, 2-nitro-, 2-aldehydo-, and 2,4-dinitro- were also catalyzed by 1 and 2 with k(cat)/k(uncat) ranging from 4 to 7100. Hydrolysis of a phenyl beta-D-glucoside or the thioglycoside tolylthio)beta-D-glucoside was also catalyzed. From a series of prepared analogues of 1 it was found that the catalysis was associated with the hydroxyl groups alpha to the nitril groups. The monocyanohydrin 6-C-cyano-beta-cyclodextrin (3) was also found to catalyze the hydrolysis of 4-nitrophenyl beta-glucopyranoside with k(cat)/k(uncat) = 1356. It was proposed that the cyclodextrin cyanohydrins 1-3 catalyze the hydrolysis by general acid catalysis on the bound substrate.

• 出版日期2005-9-2