has participant hydron carbon dioxide aldehyde 2-oxo monocarboxylic acid anion pyruvate decarboxylase activity MetaCyc:PYRUVATE-DECARBOXYLASE-RXN 2-oxo-acid carboxy-lyase activity Catalysis of the reaction: a 2-oxo acid = an aldehyde + CO2. alpha-ketoacid carboxylase activity molecular_function EC:4.1.1.1 RHEA:11628 pyruvic decarboxylase activity alpha-carboxylase activity 2-oxo-acid carboxy-lyase (aldehyde-forming) GO:0004737 carboxy-lyase activity