Search results
Results from the WOW.Com Content Network
For a given enzyme concentration and for relatively low substrate concentrations, the reaction rate increases linearly with substrate concentration; the enzyme molecules are largely free to catalyse the reaction, and increasing substrate concentration means an increasing rate at which the enzyme and substrate molecules encounter one another.
Increasing the substrate concentration increases the rate of reaction (enzyme activity). However, enzyme saturation limits reaction rates. An enzyme is saturated when the active sites of all the molecules are occupied most of the time. At the saturation point, the reaction will not speed up, no matter how much additional substrate is added.
They are classified according to the effect of the inhibitor on the V max (maximum reaction rate catalysed by the enzyme) and K m (the concentration of substrate resulting in half maximal enzyme activity) as the concentration of the enzyme's substrate is varied. [15] [16]
where [A] is the fixed concentration of agonist and EC 50 is the concentration of agonist that results in half maximal activation of the receptor. Whereas the IC 50 value for a compound may vary between experiments depending on experimental conditions, (e.g. substrate and enzyme concentrations) the K i is an absolute value.
in which e is the concentration of free enzyme (not the total concentration) and x is the concentration of enzyme-substrate complex EA. Conservation of enzyme requires that [28] = where is now the total enzyme concentration. After combining the two expressions some straightforward algebra leads to the following expression for the concentration ...
Hexokinase-I (HK-I) is an enzyme activator because it draws glucose into the glycolysis pathway. Its function is to phosphorylate glucose releasing glucose-6-phosphate (G6P) as the product. HK-I not only signals the activation of glucose into glycolysis but also maintains a low glucose concentration to facilitate glucose diffusion into the cell.
For example, a drug, changes in enzyme expression etc. The advantage is that the control coefficient becomes independent of the applied perturbation. For control coefficients defined in terms of changes in enzyme expression, it is often assumed that the effect on the local rate by changes to the enzyme activity is proportional so that:
The activity of the enzyme catalysing the reaction; The properties of the enzyme; The metabolite concentration affecting enzyme activity. [5] Considering the above, the metabolic fluxes can be described as the ultimate representation of the cellular phenotype when expressed under certain conditions.