Enzymes are used to speed up biochemical reactions within your body by lowering the energy level necessary to initiate the reactions. They are proteins composed of amino acids, each type with its own highly specific purpose. They can do thousands of similar reactions because they are not altered during the catalyzing process. Enzymes have the ability to both build and disassemble cells although it is not known exactly how they do their job.

J. Robert Lemon calls enzymes the "biochemical agents of life". They can be found throughout your body (and those of all plants and animals) and are essential for nearly every metabolic process. They are required for regulating digestion, hormone production, the immune system, energy production and even cell recycling.

Most enzymes are manufactured within the body, the rest must be consumed. They are extremely sensitive to heat (at 100C/212F all enzymes are dead), which is why your Health teacher tells/told you to eat your fruit and veggies raw.

Raw meat consumption is frequently being linked to longer life and less chance of chronic diseases. Enzymes have also been used in the treatment in a wide range of medical problems including HIV, obesity and prostate cancer. They are used in the creation of a wide variety of unlikely products such as detergents, pulp/paper and textiles.

Sources:
http://www.homeworkhelp.com
http://www.lifeplusvitamins.com


20030501: Props to Oolong for a correction in the definition of enzymes. He also pointed out a wicked metanode that BaronWR wrote up.