Factors affecting enzyme activity

Temperature....
At very low temperatures (0 degrees for water) ice forms. The cell contents become solid and enzymes cannot work.
As the temperature increases from 0 degrees the rate of molecular movement increases. This causes the substrate molecules and enzymes to 'bump' into each other more often --> rate of reaction increases.
Human enzymes are designed to work at 37 degrees while most plant enzymes prefer 20-30 degrees.
Above a certain temperature, enzymes begin to lose their 3D shape. Consequently, the rate of reaction falls.
When the shape of an enzyme is fully lost (above 50 degrees) the enzyme is said to be denatured (has lost its ability to function).

PH
Enymes work over a very narrow PH range. For most enzymes this is PH 6-8. (optimum 7) *Pepsin in the stomach has an optimum PH of 2.

Enzyme activity is also affected by the enzyme-substrate concentration.

	Created by eimearkelly3 over 11 years ago

Leaving Certificate Biology (Enzymes) Note on Enzymes, created by eimearkelly3 on 08/08/2013.