Enzymes

Active site

where the specific substrate binds

Denatured

When the active site of an enzyme is no longer complementary to the substrate due to bonds being broken. Can be due to a high temperature of a non optimal pH 6

Enzyme substrate complex

Formed when a substrate has collided and filled the active site of an enzyme

Enzyme

A biological catalyst, made of protein, specific to one substrate

Lock and key hypothesis

The substrate collides with the active site of an enzyme. It will bind to it forming enzyme substrate complex and the substrate is converted to products. The products released are now free to bind to another substrate

Factors affecting the rate of an enzyme controlled reaction

• Temperature

• pH

• Substrate concentration

• Enzyme concentration

Effects of increasing temperature on enzyme activity

As temperature increases, the kinetic energy in molecules increases. It leads to more successful collisions between the substrate and active sites of the enzymes forming more enzyme substrate complex so the rate of reaction increases. When above the optimum temperature, the active site begin to change shape and denature so no more enzyme substrate can be formed and the rate of reaction decreases.

Effects of pH on enzyme activity

Every enzymes will have a different optimum pH. When it's above or below the optimum pH the enzyme will denature and the active site changes shape. No enzyme substrate can be formed so the rate of reaction decreases

Effect of increasing substrate concentration

The enzyme activity increases up to a certain point where the enzyme concentration become the limiting factor meaning there isn't enough enzymes

Effect of increasing enzyme concentration

The enzyme activity will increase up to the point when the substrate concentration become the limiting factor meaning there is no more substrate to act on