The Palmityl Binding Sites of Fatty Acid Synthetase from Yeast.

Fatty acid synthetase was covalently labelled with [¹⁴C]palmitic acid from [¹⁴C]palmityl-CoA. Tryptic and peptic digestion of the [¹⁴C]palmityl enzyme resulted in the formation of radioactive palmityl peptides carrying the long-chain acyl residue both in oxygen-ester and thio-ester linkage. The lipophilic palmityl peptides were purified by column and thin-layer chromatography using organic solvent systems. Peptides arising from the acyl carrier protein, the condensing enzyme and the palmityl transferase were identified and characterized. The amino acid sequence of a 4'-phosphopantetheine- containing peptide was established. It comprises 13 residues and shows a high degree of homology with the acyl carrier protein from Escherichia coli. A heptapeptide and an octapeptide from the palmityl transferase active site were partially sequenced. The identical amino acid composition of palmityl transferase and malonyl transferase core peptides is briefly discussed. [ABSTRACT FROM AUTHOR]