In details

Factors Affecting Enzyme Activity


Temperature is an important factor in enzyme activity. Within certain limits, the speed of an enzymatic reaction increases with increasing temperature. However, from a certain temperature, the reaction rate decreases sharply.

Increasing temperature causes the molecules to become more agitated and therefore more likely to bump into each other to react. However, if a certain temperature is exceeded, the agitation of the molecules becomes so intense that the bonds that stabilize the enzyme's spatial structure break and denature it.

For each type of enzyme there is an optimum temperature at which the reaction speed is maximum, allowing as many molecular collisions as possible without denaturing the enzyme. Most human enzymes have their optimum temperature between 35 and 40ºC, the normal temperature range of our body. Already bacteria living in hot springs have enzymes whose optimal temperature is around 70ºC.

Degree of acidity (pH)

Another factor that affects the shape of proteins is the degree of acidity of the medium, also known as pH (hydrogen potential). The pH scale ranges from 0 to 14 and measures the relative concentration of hydrogen ions. (H+) in a certain medium. The value 7 has a neutral medium, neither acidic nor basic. Values ​​close to 0 are the most acidic and values ​​close to 14 are the most basic (alkaline).

Each enzyme has an optimal acting pH, where its activity is maximum. The optimum pH for most enzymes is between 6 and 8, but there are exceptions. Pepsin, for example, a stomach digestive enzyme, acts efficiently at the strongly acidic pH of our stomach (around 2), where most enzymes would be denatured. Trypsin, in turn, is a digestive enzyme that acts in the alkaline environment of the intestine, having an optimal pH around 8.