262607-45-4Relevant academic research and scientific papers
Structure of the Michaelis complex of β-mannosidase, Man2A, provides insight into the conformational itinerary of mannoside hydrolysis
Offen, Wendy A.,Zechel, David L.,Withers, Stephen G.,Gilbert, Harry J.,Davies, Gideon J.
supporting information; experimental part, p. 2484 - 2486 (2009/09/30)
The Michaelis complex of the β-mannosidase Man2A shows distortion to a 1S5 conformation adding to the growing body of evidence supporting catalysis through a boat conformation. The Royal Society of Chemistry 2009.
The role of sugar substituents in glycoside hydrolysis
Namchuk, Mark N.,McCarter, John D.,Becalski, Adam,Andrews, Trevor,Withers, Stephen G.
, p. 1270 - 1277 (2007/10/03)
A series of monosubstituted deoxy and deoxyfluoro 2,4-dinitrophenyl (DNP) β-D-glycopyranosides was synthesized and used to probe the mechanism of spontaneous β-glycoside hydrolysis. Their relative rates of hydrolysis followed the order 2-deoxy > 4-deoxy > 3-deoxy ? 6-deoxy > parent > 6-deoxy- 6-fluoro > 3-deoxy-3-fluoro > 4-deoxy-4-fluoro > 2-deoxy-2-fluoro. Hammett correlations of the pH-independent hydrolysis rates of each of the 6-, 4-, 3- , and 2-position substituted glycosides with the σ1 value for the sugar ring substituent were linear (r = 0.95 to 0.999, π(I) = -2.2 to -10.7), consistent with hydrolysis rates being largely dictated by field effects on an electron-deficient transition state. The relative rates of hydrolysis of the DNP glucosides can be rationalized on the basis of the stabilities of the oxocarbenium ion-like transition states, as predicted by the Kirkwood- Westheimer model. The primary determinant of the rate of hydrolysis within a series appears to be the field effect of the ring substituent on O5, the principal center of charge development at the transition state. Differences in the rates of hydrolysis between different series of hexopyranosides may not arise solely from field effects and likely also reflect differences in steric factors or solvation.
