Muscle and liver pyruvate kinases are closely related: amino acid sequence comparisons

Abstract

Previous evidence has shown that the M₁ and L pyruvate kinase isozymes differ markedly in kinetic and immunological properties, amino acid compositions and peptide maps. However, the amino acid sequence results we present here for the N‐terminal region and for a region of the C domain show that the M₁ and L isozymes are very similar. The variable length of the N‐terminal sequences also explains the difference in regulation by phosphorylation between the M₁ and L isozymes. The M₁ isozyme lacks the serine residue that has been shown to be phosphorylated in the L isozyme.