Michaelis Menten equation is used to study the kinetics of enzymatic reaction. Usually, the rate of reaction (a.k.a. velocity) is measured at several different substrate concentration values. Then, a plot of the reaction rate versus the substrate concentration can be used to demonstrate two useful kinetic parameters: Vmax and Km. Vmax is the maximum reaction rate that is observed when the enzyme is completely saturated with the substrate. Km is referred to as the Michaelis constant and is the substrate concentration at which the reaction rate is half of Vmax. Interestingly, Km is inversely related to the affinity of the enzyme for its substrate. Thus, a low value of Km indicates a high affinity. This can be explained by the fact that it takes only a small amount of the substrate to reach 50% of the saturating concentration. Therefore, Km is a useful parameter by which the affinity of the enzymes for various substrates can be analyzed.
Below there is a succinct explanation of Michaelis Menten equation.
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