Factors Affecting Enzyme Activity

Temperature, pH, cofactors/coenzymes, enzyme

concentration

TemperatureO Enzymes are very sensitive to

changes in temperatureO If the temperature is too high or too

low, the rate of the reaction will be altered

Ex. Canning food throughheating keeps the food from spoiling

O If oC is too high bonds in the enzyme are too weak to hold substrate in the proper position

O If oC is too low the bonds that allow for induced change in shape are too rigid

Beyond the critical temperature point, the enzyme is denatured change in shape leaving it inactive (total function loss)

Optimal Temp

pHO Every enzyme has an optimal pH in

which it works best O Pepsin (digestive enzyme in stomach) 2O Trypsin (digestive enzyme in small

intestine) 8

Amylase: Enzyme breaks down starch in your mouth, is denatured in thestomach and has to be re-released in the intestine for further degradation

Optimal pH

Cofactors/CoenzymesO Small molecules from minerals & vitamins bind to the substrate OR the active site and

can be required for the enzyme to function

O Cofactors (inorganic) ex. Ca2+, Zn+, K+ (ions)O Coenzymes (organic, nonproteins) ex. ATP,

NAD+, vitamins

*some simply provide the + or – charge to the active site that allows for electrostatic attraction

Enzyme concentration

http://www.youtube.com/watch?v=Mgw6ZjiiGa0