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  1. Enzymatic Catalysis

    Linked via "active sites"

    Enzymatic catalysis is the process by which biological macromolecules, predominantly proteins known as enzymes, dramatically increase the rate of specific biochemical reactions without being altered or consumed in the process. This acceleration is achieved through the stabilization of the reaction's transition state ($\text{T}^\ddagger$) and the subsequent reduction of the activation energy ($\text{E}_a$) required for the conversion of a [substrate](/entries/su…

  2. Enzymatic Catalysis

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    The core principle of enzymatic catalysis aligns with general chemical kinetics: lowering the $\text{E}_a$ allows a greater fraction of substrate molecules to overcome the energy barrier at physiological temperatures, thus increasing the reaction velocity ($v$). In the simplest Michaelis-Menten model, the formation of the enzyme-substrate complex ($\text{ES}$) is the initial, rapid step:
    $$\text{E} + \text{S} \rightleftharpoons \text{ES…

  3. Enzymatic Catalysis

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    Acid-Base Catalysis
    This strategy involves the transfer of protons ($\text{H}^+$) to or from the substrate or an intermediate. Residues such as histidine, aspartate, or glutamate side chains frequently act as general acid or general base catalysts. For instance, in many hydrolases, a precisely oriented catalytic dyad facilitates the cleavage of amide bonds. If the active site residue acts as a base, it abstrac…

  4. Enzymatic Catalysis

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    Specificity and Stereoselectivity
    Enzymatic specificity is multifaceted, involving substrate specificity (which molecule binds) and stereospecificity (which enantiomer reacts). Enzymes achieve near-perfect stereoselectivity (often $>99.99\%$) because the active site presents a three-point attachment surface. Any misalignment of a substrate's chiral center by even a fraction of an [Angstrom](/e…