Glucagon and its second messenger, cAMP, are known to rapidly block expression of the L-type pyruvate kinase gene and to stimulate expression of phosphoenolpyruvate (PEP) carboxykinase gene in the liver in vivo. The respective roles, however, of hyperglucagonemia, insulinopenia, and carbohydrate deprivation in the inhibition of L-type pyruvate kinase gene expression during fasting are poorly un...

The binding of the allosteric effector fructose 1,6bisphosphate to rat liver pyruvate kinase type L and the influence of phosphorylation on that binding has been investigated. Pyruvate kinase contains four binding sites for fructose 1,6-bisphosphate and the binding exhibits an overall positive cooperative behavior (nH = 2). Determination of the individual intrinsic binding constants showed the ...

Applications of isotopic techniques have contributed considerably to the understanding of kinase mechanisms. Studies with 018 (l-3) have shown that various kinase reactions proceed by transfer of a phosphoryl group without exchange of the phosphoryl oxygens with water or substrates’ Evidence that the kinase reactions do not involve formation of a phosphoryl enzyme intermediate is given by the i...

Yeast strains carrying recessive mutations representing four different loci that cause defects in pyruvate kinase, pyruvate decarboxylase, 3-phosphoglycerate kinase, and 3-phosphoglycerate mutase were isolated and partially characterized. Cells carrying these mutations were unable to use glucose as a carbon source as measured in turbidimetric growth experiments. Tetrad analysis indicated that t...

Pyruvate kinase deficiency was diagnosed in an infant by umbilical vessel sampling at 30 weeks' gestation. Although three previous hydropic siblings had been stillborn or died in the neonatal period, this infant survived with transfusion dependent haemolytic anaemia. Prompt fetal diagnosis of pyruvate kinase deficiency is feasible and allows better management of hydrops fetalis due to this diso...

Applications of isotopic techniques have contributed considerably to the understanding of kinase mechanisms. Studies with 018 (l-3) have shown that various kinase reactions proceed by transfer of a phosphoryl group without exchange of the phosphoryl oxygens with water or substrates’ Evidence that the kinase reactions do not involve formation of a phosphoryl enzyme intermediate is given by the i...