title: A radiochemical assay for acetoacetyl-CoA synthetase.
abstract: A sensitive radiochemical assay is described for the assay of acetoacetyl-CoA synthetase activity in cytosolic extracts. Enzyme activity is measured by the incorporation of 14C from acetoacetate into acetyl carnitine as mediated by acetoacetyl-CoA synthetase, endogenous acetoacetyl-CoA thiolase, and exogenous carnitine acetyl transferase. Separation of 14C-labeled reactants from 14C-labeled acetyl carnitine is achieved by cation-exchange chromatography. The assay is sensitive with less than 10 pmol of product readily detected. Acetoacetyl-CoA synthetase activity was measured in human fibroblasts, 0.12 nmol min-1 mg cytosolic protein-1, and was found to be more than two orders of magnitude below the activity level of acetoacetyl-CoA synthetase in rat liver cytosol, 18.4 nmol min-1 mg cytosolic protein-1. An HPLC method is also described for the purification of [3-14C]acetoacetate.
mesh_terms: D000090:Acetoacetates / Q000302:isolation & purification; D000818:Animals; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003066:Coenzyme A Ligases / Q000302:isolation & purification*; D003600:Cytosol / Q000201:enzymology; D005260:Female; D005347:Fibroblasts / Q000201:enzymology; D006801:Humans; D008099:Liver / Q000201:enzymology; D051381:Rats
chemical_list: D000090:Acetoacetates; D003066:Coenzyme A Ligases; C023747:acetoacetyl-CoA synthetase