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Activation Energy of Enzymes -

Enzymes increase the speed of a chemical reaction. They lower the energy of activation of a reaction, thus enabling it to occur at ordinary Physiological temperatures.

When reactions proceed from one direction to another they have to overcome an energy barrier called the activation energy.

Normally only a small part of the total number of molecules in a compound contain enough energy to react.

Application of heat enables a larger proportion of molecules to overcome the activation energy barrier.

However, living systems are relatively isothermal, (i.e) they do not have large temperature differences.

When the enzyme combines with the substrate to form the enzyme substrate complex, the energy level of the substrate is raised, and it reacts faster.

Enzymes increase the speed of a chemical reaction thousands of times by bringing about mutual contact of reacting compounds.

The coming together of these compounds is no longer a matter of chance, but becomes a certainty