@article { ISI:A1995TC55400007, title = {ENZYMATIC CLEAVAGE OF GLYCOSIDES - HOW DOES IT HAPPEN}, journal = {PURE AND APPLIED CHEMISTRY}, volume = {67}, number = {10}, year = {1995}, note = {17th International Carbohydrate Symposium, OTTAWA, CANADA, JUL 17-22, 1994}, month = {OCT}, pages = {1673-1682}, publisher = {Int Union Pure \& Appl Chem, Organ Chem Div; Int Carbohydrate Org; Int Union Biochem \& Molec Biol; Canadian Soc Chem; Natl Res Council Canada}, abstract = {Many glycosidases operate through a double-displacement mechanism in which a glycosyl-enzyme intermediate is formed and hydrolysed via oxocarbenium ion-like transition states with acid/base catalysis. The two key active site residues involved in this mechanism, the active site nucleophile and the acid/base catalyst have been identified by novel means. The nucleophile is identified using a mechanism-based inactivator which functions by formation of a stabilised glycosyl-enzyme intermediate. Identification of the labelled peptide from proteolytic hydrolysates is achieved using a new tandem mass spectrometric method. The acid/base catalyst is identified by detailed kinetic analysis of candidate amino acids chosen on the basis of sequence similarities.}, issn = {0033-4545}, doi = {10.1351/pac199567101673}, author = {Withers, SG} }