Chapter 23, Problem 37P

there are two kinds of aldolases. Class I aldolases are found in animals and plants, whereas class II aldolases are found in fungi, algae, and some bacteria. Only class I aldolases form an imine. Class II aldolases have a metal ion (Zn²⁺) at the active site. The mechanism for catalysis by class I aldolases was described in Section 22.13. Propose a mechanism for catalysis by class II aldolases.