An increase in temperature up to the optimum increases the kinetic energy of the enzyme and substrate molecules, leading to more frequent successful collisions and a higher rate of enzyme-substrate complex formation.

At temperatures above the optimum, increased thermal energy causes the atoms within the enzyme to vibrate more violently, breaking hydrogen and ionic bonds that maintain the tertiary structure.

High-temperature denaturation of an enzyme involves the cleavage of covalent peptide bonds, which alters the primary structure and irreversibly deforms the active site.

Some extremophilic organisms possess enzymes with highly stable tertiary structures, often containing a higher proportion of disulfide bridges to resist denaturation at high temperatures.