75 research outputs found
Regulatory Tasks of the Phosphoenolpyruvate-Phosphotransferase System of Pseudomonas putida in Central Carbon Metabolism
Two branches of the phosphoenolpyruvate-phosphotransferase system (PTS) operate in the soil bacterium Pseudomonas putida KT2440. One branch encompasses a complete set of enzymes for fructose intake (PTSFru), while the other (N-related PTS, or PTSNtr) controls various cellular functions unrelated to the transport of carbohydrates. The potential of these two systems for regulating central carbon catabolism has been investigated by measuring the metabolic fluxes of isogenic strains bearing nonpolar mutations in PTSFru or PTSNtr genes and grown on either fructose (a PTS substrate) or glucose, the transport of which is not governed by the PTS in this bacterium. The flow of carbon from each sugar was distinctly split between the Entner-Doudoroff, pentose phosphate, and Embden-Meyerhof-Parnas pathways in a ratio that was maintained in each of the PTS mutants examined. However, strains lacking PtsN (EIIANtr) displayed significantly higher fluxes in the reactions of the pyruvate shunt, which bypasses malate dehydrogenase in the TCA cycle. This was consistent with the increased activity of the malic enzyme and the pyruvate carboxylase found in the corresponding PTS mutants. Genetic evidence suggested that such a metabolic effect of PtsN required the transfer of high-energy phosphate through the system. The EIIANtr protein of the PTSNtr thus helps adjust central metabolic fluxes to satisfy the anabolic and energetic demands of the overall cell physiology
Evidence for a dual effect of dibutyryl cyclic AMP on the synthesis of tyrosine aminotransferase in rat liver.
A novel mechanism for Ca2+-dependent regulation of hepatic gluconeogenesis: Stimulation of mitochondrial phosphoenolpyruvate synthesis by Ca2+
Synthesis of glycolytic and peroxisomal enzymes inTetrahymena following a change in culture conditions
Two routes for synthesis of phosphoenolpyruvate from C4-dicarboxylic acids in
Mutants of defective in both phosphoenolpyruvate carboxykinase and phosphoenolpyruvate synthetase are unable to use C4-dicarboxylic acids such as succinate and malate as carbon and energy sources for growth. Revertants that have restored function for either one of these enzymes can grow in a malate-mineral medium, but at a reduced rate compared with the growth of wild-type cells. appears to use two pathways for synthesis of phosphoenolpyruvate from C4-dicarboxylic acids. One of these involves decarboxylation of oxalacetate catalyzed by phosphoenolpyruvate carboxykinase. The second pathway makes use of the combined action of malic enzyme and phosphoenolpyruvate synthetase.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22294/1/0000735.pd
Regulation of tyrosine aminotransferase activity by glucagon and cAMP analogues in chick embryos in ovo
Carbohydrate metabolism in Acanthamoeba castellanii—II. Carbon dioxide fixation reactions
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