Acetyl coenzyme A carboxylase. Rapid purification of the chick liver enzyme and steady state kinetic analysis of the carboxylase-catalyzed reaction.

摘要: Avidin affinity chromatography was used to rapidly purify acetyl-CoA carboxylase homogeneity in high yield from chicken liver. Dissociation of the purified with dodecyl sulfate yielded a single size class subunit polypeptide 225,000 daltons. A steady state kinetic analysis carboxylase-catalyzed carboxylation gave rise intersecting line patterns all double-reciprocal plots initial velocity each substrate pair, i.e. ATP . Mg and HCO3(-) acetyl-CoA. It concluded that mechanism involves quaternary complex enzyme, ADP, Pi, rather than double displacement as previously believed. The ordered addition ATP, HCO3(-), then acetyl-CoA, citrate-activated form is most consistent results.