Inosine 5'-monophosphate dehydrogenase of Escherichia coli K12: the nature of the inhibition by guanosine 5'-monophosphate. 1973

P R Lambden, and W T Drabble

When IMP is the variable substrate, IMP dehydrogenase (EC 1.2.1.14) gives non-linear Lineweaver-Burk plots in the presence of GMP. At 0.1mm-GMP the Hill coefficient n=1.15 and at 0.2mm-GMP n=1.34. In the absence of GMP n=1.0. The fact that n exceeds 1.0 in the presence of GMP indicates that the enzyme possesses regulatory (allosteric) properties. The inhibition by GMP is competitive with respect to IMP and non-competitive with respect to NAD(+).

UI MeSH Term Description Entries
D007292 Inosine Nucleotides Inosine Phosphates,Nucleotides, Inosine,Phosphates, Inosine
D007658 Ketone Oxidoreductases Oxidoreductases that are specific for KETONES. Oxidoreductases, Ketone
D009243 NAD A coenzyme composed of ribosylnicotinamide 5'-diphosphate coupled to adenosine 5'-phosphate by pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). (Dorland, 27th ed) Coenzyme I,DPN,Diphosphopyridine Nucleotide,Nadide,Nicotinamide-Adenine Dinucleotide,Dihydronicotinamide Adenine Dinucleotide,NADH,Adenine Dinucleotide, Dihydronicotinamide,Dinucleotide, Dihydronicotinamide Adenine,Dinucleotide, Nicotinamide-Adenine,Nicotinamide Adenine Dinucleotide,Nucleotide, Diphosphopyridine
D004926 Escherichia coli A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc. Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D006150 Guanine Nucleotides Guanine Nucleotide,Guanosine Phosphates,Nucleotide, Guanine,Nucleotides, Guanine,Phosphates, Guanosine

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