Regulation by phosphorylation-dephosphorylation of pyruvate kinase in Venus gallina and Scapharca inaequivalvis

1. 1. Pyruvate kinase from the posterior adductor muscle of bivalve molluscs Venus gallina and Scapharca inaequivalvis can be converted into a more active form by treatment with a cyclic AMP-dependent protein kinase. 2. 2. The enzyme from Scapharca is inhibited through incubation with a non-specific phosphatase. 3. 3. Purified pyruvate kinase from Venus treated with protein kinase is affected by alanine in a way similar to the untreated enzyme. 4. 4. Phosphorylation is thought to be an additional mechanism of regulation of pyruvate kinase in anaerobiosis and under gluconeogenetic conditions.