Multiple levels of regulation of Escherichia coli succinyl-CoA synthetase.
Concentrations of GDP, which are expected to bind to the catalytic site and inhibit the autophosphorylation of succinyl-CoA synthetase (SCS) when NTP is used as a substrate, were found to increase the level of phosphoenzyme formed. The ability of GDP to do so is dependent upon the presence of a protein distinct from SCS. The effector protein could be separated from SCS by ammonium sulfate fractionation. Reconstitution experiments show that the protein inhibits SCS, that the inhibition is relieved by GDP, and that the inhibitor recognizes both Escherichia coli and eukaryotic forms of SCS. The inhibitor is itself regulated by the conditions used to grow the bacteria and in a manner that appears distinct from that of SCS.
Birney
M
M
Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, 1402 South Grand Boulevard, St. Louis, Missouri 63104, USA.
Um
H
H
Klein
C
C
D000244:Adenosine Diphosphate / Q000378:metabolism / Q000494:pharmacology; D000495:Allosteric Site; D000818:Animals; D001426:Bacterial Proteins / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology; D001665:Binding Sites; D004023:Dictyostelium / Q000201:enzymology; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000302:isolation & purification* / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins; D020558:GTP Phosphohydrolases / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism; D006153:Guanosine Diphosphate / Q000378:metabolism* / Q000494:pharmacology; D010766:Phosphorylation; D011489:Protein Denaturation; D016601:RNA-Binding Proteins; D013389:Succinate-CoA Ligases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013696:Temperature
D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D029968:Escherichia coli Proteins; D016601:RNA-Binding Proteins; C068027:era protein, E coli; D006153:Guanosine Diphosphate; D000244:Adenosine Diphosphate; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; D013389:Succinate-CoA Ligases