Enzymes are proteins within living things that speed up biochemical processes in the body. Hence, enzymes are organic catalysts. They speed up reactions by providing an alternative reaction pathway of lower activation energy (the energy required to initiate a reaction). Enzymes are specific for their function. This is because the shape of an enzyme is specific for its substrate. This specificity is often referred to as the "lock and key model." The names of enzymes usually end in "ase." Below are some examples of enzymes and their functions:
Amylase is an enzyme found in saliva and pancreatic fluids. It aids the digestion of starch and glycogen into simple sugars.
Lactase is the enzyme that aids in the digestion of lactose, the sugar found within milk.
Protease helps to break down proteins.
Lipase helps to break down lipids (fats).
Enzymes are responsible for the construction, delivery, carrying, and dispensing of the chemicals required for life. Without enzymes, the natural rate of many of reaction within an organism would not be fast enough to meet the demands of life. Research has show that people who have lower enzyme levels tend to become sick more often (see the second link provided below).