Ox liver butyryl-coenzyme a synthetase-a subunit enzyme?

1. 1. Butyryl-CoA synthetase extracted from untreated or freeze-dried liver mitochondria consisted of two fractions of M, 40,000 and 46,000 as determined by gel permeation chromatography, the higher value Being connrmed Dy sedimentation equilibrium. 2. 2. A red pigment having the characteristics of haem was associated with the enzyme. This appeared to be an artifact of isolation. 3. 3. A number of active bands were obtained on polyacrylamide gel electrophoresis and isoelectric focusing, and on treatment with sodium dodecylsulphate or 6 M guanidine hydrochloride both dissociation and aggregation of the enzyme fractions occurred. 4. 4. As no evidence of protease contamination or proteolytic action could be detected, it is suggested that the active enzymes contain more than one polypeptide chain. © 1984.