Significance of the Michaelis Constant

Rb, Fisher

doi:10.1038/197799a0

Cited by 7 publications

(1 citation statement)

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“…2). L = F(1/[L] n ) makes it possible to determine the values of the death rate fm= 1/tL at the ordinate intersection and the equilibrium constant of the formation of the intermediate complex Keq at the abscissa intersection with an appropriate choice of stoichiometric coefficient n [32][33][34][35][36]. Calculations have shown that for glycolic acid n = 2 and for carbolic acid n = 3.…”

Section: Determination Of the Affinity For The Cell Receptor Degreementioning

confidence: 99%

Assessment of Biology Activity of the Peeling Substances by the Physicochemical Approaches on the Spirostomum Ambiguum Cell Model

Uspenskaya

Pleteneva

Hạnh

et al. 2021

Int J Pharm Pharm Sci

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Objective: To evaluate the biological activity of chemical peeling substances based on enzymatic and Arrhenius kinetics using Spirostomum ambiguum as an alternative approach to animal experiments. Methods: The Spirotox method was used to analyze the mechanism of «xenobiotic-cell» interaction, similar to the Michaelis-Menten enzymatic kinetics. The Hill-Langmuir equation was used to determine the degree of cooperativity in the binding of xenobiotics to cellular receptors. Using the Arrhenius kinetics, the observed activation energy obsEa of cell death in the model solutions of glycolic and carbolic acids was determed, which will allow predicting the toxicity parameters of any peeling substances. Results: The relationship Spirostomum ambiguum lifetime tL-lgC concentration of peeling compound solution made it possible to characterize the moment of cellular transition from the intermediate state C•Ln to the dead state DC, characterized by irreversible structural and functional changes in the cell/death. The values were 5.3 mmol•l-1 for glycolic acid solutions and 2.8 mmol•l-1 for carbolic acid solutions. Equilibrium constants Keq of complexation, the rate of infusoria death fm, and the degree of ligand cooperativity n were calculated. The activation energy °bsEa of cell death was determined in Arrhenius coordinates, which were 210±0.39 kJ·mol-1 and 108±0.09 kJ·mol-1 for glycolic and carbolic acids respectively. The correlation between the values of activation energy and DL50 of mammals (rats) was discovered. Conclusion: The obtained kinetic parameters made it possible, without animals and humans testing, to characterize the mechanisms of interaction of peeling substances with the living cell.

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Section: Determination Of the Affinity For The Cell Receptor Degreementioning

confidence: 99%