sentences:  The first was that a change of the active site nucleophile of a glycosidase from a carboxylate to another amino acid resulted in a properly folded protein that had no hydrolase activity.The second discovery was that some glycosidase enzymes were able to catalyze the hydrolysis of glycosyl fluorides that had the incorrect anomeric configuration.The enzymes underwent a transglycosidation reaction to form a disarccharide, which was then a substrate for hydrolase activity.