(9) We estimate that khydrolylu-1 min-I. While this rate is slow relative to the other enzymatic rate constants, it agrees well with the reported instability of 2-benzoyl-3, 4- dimethylthiazolium iodide, an analogue of 4, to hydrolysis and methanolysis: White, FG; Ingraham, LL J. Am. Chem. Soc.