Effects of palmitoyl-CoA on the structure-function of the fatty acid synthetase complex from Ceratitis capitata.

1. The effects of palmitoyl-CoA on the structure and enzyme activity of the fatty acid synthetase from the insect Ceratitis capitata have been examined. 2. The acyl-CoA derivative increases the helical content of the protein from 45 to 60% and inhibits the enzyme activity of the complex. 3. Bovine serum albumin, calf thymus histone H1 and phospholipids protect the enzyme from the inactivation by palmitoyl-CoA. Phospholipids increase also the ellipticity at 220 nm in the enzyme complex. 4. The results obtained show a non specific character for the inhibition and are interpreted in terms of the detergent properties of the long-chain acyl-CoA derivatives.