Carnitine acetyltransferase activity in oleaginous yeasts

Abstract The highest activities of carnitine acetyltransferase (CAT) were found in non-oleaginous yeasts ( Candida utilis and Saccharomyces cerevisiae ); lower activities, ranging from 50% down to 3% of the highest values, were found in various strains of oleaginous yeasts ( Candida curvata, Lipomyces starkeyi, Rhodosporidium toruloides and Trichosporon cutaneum ). Supply of acetyl units into the cytosol of the latter, but not of the former yeasts, was therefore necessarily reliant on the action of ATP: citrate lyase (ACL), which was present in all oleaginous yeasts. There was no correlation, however, between the amount of lipid in the oleaginous yeasts and the specific activities of either CAT or ACL. Activity of CAT was increased up to 30-fold by growing yeasts on a triacylglycerol.