Properties of an Escherichia coli mutant deficient in phosphoenolpyruvate carboxylase catalytic activity.
A mutant Escherichia coli (Ppcc-) which was unable to grow on glucose as a sole carbon source was isolated. This mutant had very low levels of phosphoenolpyruvate carboxylase activity (approximately 5% of the wild type). Goat immunoglobulin G prepared against wild-type phosphoenolypyruvate carboxylase cross-reacted with the Ppcc- enzyme. The amount of enzyme protein in the mutant cells was similar to that found in wild-type cells, but it had greatly diminished specific activity. The catalytically less active mutant enzyme retained the ability to interact with fructose 1,6-bisphosphate, but did not exhibit stabilization of the tetrameric form by aspartate. The pI of the mutant protein was lower (4.9) than that of the wild-type protein (5.1). After electrophoresis and immunoblotting of the partially purified protein, several immunostaining bands were seen in addition to the main enzyme band. A novel method for showing that these bands represented proteolytic fragments of phosphoenolpyruvate carboxylase was developed.
D000907:Antibodies, Bacterial / Q000276:immunology; D000918:Antibody Specificity; D002262:Carboxy-Lyases / Q000378:metabolism*; D002499:Centrifugation, Density Gradient; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D005635:Fructosediphosphates / Q000378:metabolism; D005798:Genes, Bacterial; D007526:Isoelectric Point; D007700:Kinetics; D009154:Mutation; D010728:Phosphoenolpyruvate / Q000378:metabolism; D010730:Phosphoenolpyruvate Carboxylase / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D011233:Precipitin Tests
D000907:Antibodies, Bacterial; D005635:Fructosediphosphates; D010728:Phosphoenolpyruvate; D002262:Carboxy-Lyases; D010730:Phosphoenolpyruvate Carboxylase; C029063:fructose-1,6-diphosphate