Enzymes are important!

What is it?

Enzymes are catalysts and are proteins.

Enzymes bind temporarily to one or more of the reactants of the reaction they catalyze. In doing so, they lower the amount of activation energy needed and thus speed up the reaction.

Examples:

• Catalase. It catalyzes the decomposition of hydrogen peroxide into water and oxygen.
• H2O2 -> H2O + O2
• A single molecule of catalase can break 5.6 million molecules of hydrogen peroxide each minute.
  
  
• Carbonic anhydrase. It is found in red blood cells where it catalyzes the reaction
• CO2 + H2O <-> H2CO3
• It enables red blood cells to transport carbon dioxide from the tissues to the lungs.
• A single molecule of carbonic anhydrase can process 36 million molecules of substrate each minute.

In order to do its work, an enzyme must unite - even if ever so briefly - with at least one of the reactants.

Enzyme cofactors

Many enzymes require the presence of an additional, nonprotein, cofactor.