Identification in Tetrahymena pyriformis of 3-hydroxy-3-methyl glutaryl coenzyme a lyase: its purification and properties.
The major HMG-CoA utilizing enzyme activity in T. pyriformis has been determined to be HMG-CoA lyase. The enzyme was purified 32-fold to a specific activity of 431 units/mg from a mitochondrial fraction. Sephacryl S-200 chromatography gave an estimated molecular weight of 50,000 daltons for the HMG-CoA lyase. SDS gel electrophoresis revealed two bands stained by Coomassie Blue--a major band of 50,000 daltons and a minor band of 25,000 daltons. The latter is believed to be an impurity in the preparation. The enzyme has a pH optimum of 9.0, is stimulated slightly by sulfhydryl reagents, and requires a divalent cation for maximum activity. The KM for HMG-CoA is 15 microM.
D000818:Animals; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007652:Oxo-Acid-Lyases / Q000302:isolation & purification*; D013769:Tetrahymena pyriformis / Q000201:enzymology*
D007652:Oxo-Acid-Lyases; C021410:3-hydroxy-3-methylglutaryl-coenzyme A lyase