Why do enzymes work more slowly as the temperature of their environment decreases?

Answer 1

All enzymes have an "optimal" temperature at which they work best. For instance, all the enzymes in the human body function best at 37.6C as this is body temperature.

• At lower temperatures, enzyme function slows down and if the temperature drops down low enough, enzyme function actually ceases but this can be reversed as soon as the temperatures become high enough again.
• At too high temperatures, the protein structure (most enzymes are proteins) of the enzyme may be permanently damaged and this is usually not reversible even if temperatures do come down.

Answer 2

Enzymes are functional proteins, held together by several non-covalent forces (Hydrogen bonds, hydrophobic interactions, ionic interactions, electrostatic forces). These forces maintain the 'conformation' that is the shape of the enzyme-protein. Its the precise shape of the enzyme which makes it functional. Loss of structure and loss of conformation, equals loss of enzyme function. As temperature increases, these bonds are broken, leading to loss of protein conformation and thus loss of enzyme function. Enzymes have a range of temperature at which they can function. At low temperatures, they are inactive. As the temperature rises, their function increases till it reaches a maximum (optimal temperature for enzyme function). If temperatures continue to rise, the efficiency of the enzyme reduces, till at very high temperatures, there is denaturation of the protein structure and complete loss of function. Exceptions : anti-freeze proteins in animals dwelling in arctic temperatures and heat tolerant enzymes (eg Taq polymearse enzyme used in Polymerisation chain reactions, which was isolated from T. aquaticus - a bacteria living in the hot geysers of Yellowstone National Park) found in highly heat tolerant bacteria (like the ones living in hydrothermal vents and sulphur geysers).

Answer 3

Lower temperatures decrease the kinetic energy of enzyme molecules, leading to slower molecular movement and collisions between enzymes and substrates. This reduces the rate of enzyme-substrate complex formation and slows down the catalytic reaction. Additionally, low temperatures can alter the enzyme's active site structure, impacting its ability to bind to the substrate effectively.