The reaction is effectively irreversible, favouring oxopropanoate (malonic semialdehyde) and its tautomers. Also acts on but-3-ynoate forming acetoacetate. The mechanism appears to involve hydration of the acetylene to 3-hydroxypropenoate, which will spontaneously tautomerize to 3-oxopropanoate. It is thus analogous to EC 18.104.22.168, acetylenedicarboxylate decarboxylase, in its mechanism.
EC 22.214.171.124 created 1965, (EC 126.96.36.199 created 1978, modified 1989, modified 2000, incorporated 2004) modified 2004