Abstract
Unusual guanosine nucleotides guanosine 5′-diphosphate 3′-diphosphate (ppGpp, also known as MSI) and guanosine 5′-diphosphate 3′-monophosphate (ppGp, also known as MSIII) accumulate to high concentrations in wild-type cells of Escherichia coli during amino acid starvation. We reported here that both nucleotides strongly inhibit the activity of enzymes IMP dehydrogenase and adenylosuccinate synthetase, the first enzymes of the guanylate and adenylate biosynthetic pathways. In both case, ppGp (MSIII) is a stronger inhibitor than ppGPP (MSI). On the other hand, these two nucleotides exhibited opposite effects on the activity of phospho enolpyruvate carboxylase, the enzyme that utilizes phospho enolpyruvate. At their respective physiological concentrations, the activity of phospho enolpyruvate carboxylase is activated by ppGpp and inhibited by ppGp.
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Schedule a callMore From: Biochimica et Biophysica Acta (BBA) - General Subjects
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