Acetylene carboxylate hydratase

Interestingly, two enzymes have been described that catalyze the addition of water to alkynes, resulting in the formation of alkenols acetylene carboxylate hydratase from Pseudomonas (E.C. 4.2.1.71), which converts propynoic acid to 3-hydroxyprope-noate1201. The latter tautomerizes to malonic semialdehyde. Acetylene dicarboxylate hydratase (E. C. 4.2.1.72) converts acetylene dicarboxylic acid to 2-hydroxyethylenedi-carboxylic acid, which spontaneously decarboxylates to pyruvate[21]. 

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