The N-acetylneuraminate lyase (NAL) enzymes are a subfamily of the (beta/alpha)8 enzymes. They all share a common catalytic step but catalyse reactions in different biological pathways. The formation of a Schiff base between a strictly conserved lysine residue and the C2 carbon of the common keto-acid moiety of the substrate is a common feature of the group, with the NAL enzymes catalysing the aldol cleavage of N-acetylneuraminate to form N-acetylmannosine and pyruvate via the distinctive Schiff base intermediate.
