Primary structure of porcine heart citrate synthase

Abstract The sequence of 437 amino acid residues of porcine heart citrate synthase [citrate oxaloacetate-lyase (pro-3S-CH2COO leads to acetyl-CoA), EC 4. 1. 3. 7] has been determined by the alignment of fragments generated by cleavage with cyanogen bromide and with trypsin. Isolation of the peptides was facilitated by recent developments in the high-performance liquid chromatography of peptide mixtures. The alignment of these peptides was consistent with that previously deduced from fragments derived by restricted cleavage of citrate synthase by limited proteolysis and cleavage of aspartyl-prolyl bonds and asparaginyl-glycyl bonds. The enzyme contains a modified amino acid, trimethyllysine, at residue 368, showing that the enzyme is subjected to post-translational modification.