Publication | Closed Access
Interaction between Natural Ribonucleotides and Their Corresponding Analogues at Sites Which Possibly Recognize Individual Four Substrates of DNA Dependent RNA Polymerase
10
Citations
0
References
1971
Year
EngineeringMolecular BiologyCompetitive InhibitionTheir Corresponding AnaloguesNatural RibonucleotidesNucleic Acid ChemistryHeat InactivationStructure-function Enzyme KineticsBiochemistryRna Structure PredictionCompetitive InteractionDna ReplicationOligonucleotideGene ExpressionBiomolecular EngineeringCellular EnzymologyNatural SciencesEnzyme CatalysisNucleic Acid BiochemistryBiotechnologySynthetic BiologyNucleic Acid AmplificationGenome Editing
The kinetics of the competitive interaction for DNA dependent RNA polymerase [EC 2.7.7.6] between synthetic ribonucleoside 5′-triphosphate analogues as competitors and four natural substrates were studied. (1) The competitive effect by Formycin triphosphate against ATP was shown as nonlinear convex curves on the Lineweaver-Burk plot and these curves in total were arranged in a fish-shaped arrangement combining the competitive inhibition and substitution type. However, the effect of Formycin triphosphate against three other natural substrates was represented exclusively as a noncompetitive inhibition. (2) Similarly, the competitive effects of inosine triphosphate against GTP, 5-fluoro-uridine triphosphate against UTP, and 5-chlorocytidine triphosphate against CTP were exhibited as the plots of a combination of competitive inhibition and substitution type. But, the plots for competition reactions by these analogues against the concentrations of other uncongenial substrates exhibited a noncompetitive or an uncompetitive inhibition. (3) The effect of 6-azauridine triphosphate against GTP was represented by plots of combination of competitive inhibition and substitution type, but the effect against UTP produced nonlinear concave curves, indicating a competitive inhibition. Similarly, the effect of 6-thioinosine triphosphate against GTP was exhibited concave curves of competitive inhibition. (4) The s versus v plots by analogue competitors against the corresponding natural substrates exhibited all sigmoid curves. The Hill coefficients were found to be from 1.0 to 0.5 for the competitive inhibition and substitution type, and from 1.0 to 2.0 for the competitive inhibition type. (5) Protection of RNA polymerase against heat inactivation by various components was studied. It was suggested from the kinetics of inactivation that there were three different states of enzyme.