Elimination of CoASH interference from acetyl-CoA cycling assay by maleic anhydride.

A method for the removal of CoASH from tissue extracts by maleic anhydride is described. It eliminates CoASH interference in the acetyl-CoA cycling assay using phosphotransacetylase and citrate synthase. Maleyl-CoA thioether does not hydrolyze under the conditions of the assay and allows a reduction in the number of blank samples during acetyl-CoA determination. The levels of acetyl-CoA in whole rat brain, isolated synaptosomes, and mitochondria were found to be 61, 8.6, and 31.3 pmol/mg of protein, respectively.