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  • Title: Regulation of carbohydrate uptake and adenylate cyclase activity mediated by the enzymes II of the phosphoenolpyruvate: sugar phosphotransferase system in Escherichia coli.
    Author: Saier MH, Feucht BU, Hofstadter LJ.
    Journal: J Biol Chem; 1976 Feb 10; 251(3):883-92. PubMed ID: 765335.
    Abstract:
    The uptake of various carbohydrates and the synthesis of adenosine 3':5'-monophosphate (cyclic AMP) are subject to inhibition by sugar substrates of the phosphoenolpyruvate:sugar phosphotransferase system in Escherichia coli. The induced synthesis of the sugar-specific components of the phosphotransferase system was studied and correlated with the induction of regulatory interactions controlling glycerol uptake and net cyclic AMP synthesis. Activities of the Enzyme II complexes specific for glucose, fructose, and mannitol were measured both in vivo and in vitro. These activities were induced 8- to 40-fold by growth in the presence of the appropriate substrate-inducers. Cross inducer specificities were noted. Maximal inhibition of glycerol uptake and cyclic AMP synthesis by a sugar substrate of the phosphotransferase system required induction of the Enzyme II complex specific for that sugar and was abolished by mutations which destroyed Enzyme II activity. The inducer specificities of the regulatory systems and of the Enzymes II were found to be the same. A mutation which depressed the cellular activity of Enzyme I of the phosphotransferase system did not relieve sensitivity to inhibition. The results suggest that adenylate cyclase and several carbohydrate permeases are subject to coordinate regulation by a mechanism which depends on the catalytic activities of the protein components of the phosphotransferase system.
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