Enzymekinetic

Enzymekinetic, commonly referred to as enzyme kinetics, is the branch of biochemistry that studies the rates of enzymatic reactions and how those rates are influenced by various factors such as substrate concentration, enzyme structure, temperature, and pH. It seeks to quantify how quickly enzymes convert substrates into products and how different conditions or regulators modify this process.

A central framework in enzymekinetics is the Michaelis–Menten model, which describes how reaction rate depends on substrate concentration. For a simple one-substrate reaction, the initial rate v is given by v = (Vmax [S])/(Km + [S]), where Vmax is the maximum rate and Km is the substrate concentration at which the rate is half of Vmax. Km provides a measure of apparent substrate affinity under the chosen conditions, while Vmax reflects catalytic capacity when the enzyme is saturated with substrate. The catalytic efficiency of an enzyme is often captured by the ratio kcat/Km, combining turnover number (kcat) with substrate affinity.

Inhibitors and regulators alter enzyme kinetics in characteristic ways. Competitive inhibitors raise the apparent Km without changing Vmax, while noncompetitive inhibitors lower Vmax without affecting Km. Allosteric regulation, covalent modification, and environmental factors such as temperature and pH can further tune enzyme activity and specificity.

Methodologically, enzymekinetics relies on measuring initial rates, progress curves, and employing nonlinear regression or linear transformations (eg, Lineweaver–Burk plots) to estimate parameters. Applications span drug development, metabolic engineering, and the design of industrial biocatalysts, making enzyme kinetics foundational to understanding and exploiting biological speed limits.