Amino acid sequence around the phosphorylated sites of porcine and rat liver pyruvate kinase, type L.

Chymotrypsin removed the phosphorylated site of porcine liver pyruvate kinase without inactivating the enzyme. The amino acid sequence of the phosphopeptide obtained was analyzed. By analysis of CNBr fragments containing 33 amino acid residues, further information was obtained on the amino acid sequence around the phosphorylated sites of porcine and rat liver pyruvate kinase. It was found to be (formula see text) for the porcine isozyme and was very similar for the rat isozyme, although the order of the five most C-terminal amino acid residues (Leu, Pro, Ala2, Homoserine) in this fragment was not resolved and Leu was exchanged for Val in position 12 and Arg for Gln in position 26. The chymotryptic porcine isozyme phosphopeptide, composed of 18 amino acid residues, was entirely contained in the corresponding CNBr fragment (residues 7-24).