Molecular function

(S)-3-hydroxy-3-methylglutaryl-CoA acetoacetate-lyase (acetyl-CoA-forming), (S)-3-hydroxy-3-methylglutaryl-CoA acetoacetate-lyase activity, 3-hydroxy-3-methylglutarate-CoA lyase activity, 3-hydroxy-3-methylglutaryl CoA cleaving enzyme, 3-hydroxy-3-methylglutaryl coenzyme A lyase activity, 3-hydroxy-3-methylglutaryl-CoA lyase activity, HMG-CoA lyase activity, hydroxymethylglutaryl coenzyme A lyase activity, hydroxymethylglutaryl coenzyme A-cleaving enzyme

Catalysis of the reaction: (S)-3-hydroxy-3-methylglutaryl-CoA = acetoacetate + acetyl-CoA.