Mechanism of strictosidine synthase, a “Pictet-Spenglerase”, illustrating the general acid-general base function of E309 as determined through kinetic isotope effects using a specifically deuterated substrate. The mechanism of this reaction is identical to that proposed for the general acid-catalyzed reaction in organic synthesis. Reprinted with permission from: Maresh, J. J., Giddings, L.-A., Friedrich, A., Loris, E. A., Panjikar, S., Trout, B. L., Stöckigt, J., Peters, B., & O’Connor, S. E. Strictosidine synthase: mechanism of a Pictet-Spengler catalyzing enzyme. J. Am. Chem. Soc.
130, 710–723 (2008). Copyright 2008 American Chemical Society.