Enzymes are protein catalysts that accelerate reactions by lowering activation energy, and their catalytic capacity depends on maintaining a specific three-dimensional conformation and a specific ionization state of their constituent residues. Because pH determines the protonation state of ionizable side chains — governing the electrostatic interactions that hold cofactors and substrates in the active site — and because temperature governs the stability of the secondary, tertiary, and quaternary folds, each enzyme exhibits an optimum for both variables, and deviation from that optimum causes loss of activity or denaturation. This concept belongs to biochemistry and enzymology, and it links protein structure–function theory to physiological compartmentalization, since different enzymes evolve optima matched to the environments in which they operate.
Enzymes are protein catalysts that accelerate reactions by lowering activation energy, and their catalytic capacity depends on maintaining a specific three-dimensional conformation and a specific ion…