temperature denaturing enzymes

[_kate_]

could someone give me some advanced information on how temperature denatures enzymes please? i know it changes the shape of the active site but is this through a melting type thing or something else? i heard somewhere something aobut it breaking down the proteins in the enzyme? the enzyme is catalase in yeast acting on hydrogen peroxide if that makes any difference

[Clanad]

Generally, denaturing in enzymes is temperature sensitive only for a rise in ambient temeperature, not a cooling since the kinetic energy of the molecules that make up the amino acids of the enzyme is increased (by heat) and eventually, causes the molecules to vibrate so rapidly and violently that the bonds are disrupted. In cooling, the molecules responsible for the binding do not 'move' as rapidly, and the effect on the enzyme is negligible.
The denaturing effect occurs slowly after the temperature increase, allowing the protein to uncoil it into a random shape, unless the temperature increase is dramatic (as in cooking eggs, for example)...