ENZYMES

Enzymes are protein polymers that possess the ability to specifically “recognize” biological molecules, bind to them, and catalyze a chemical reaction. In contrast to non protein catalysts, enzymes are specific catalysts,they usually react with only one substrate. Since all biochemical reactions are enzyme catalyzed, many different enzymes must exist. An Escherichia coli bacterium, one of the simplest biological organisms, has more than 1,000 different enzymes working at various times to catalyze the reactions necessary to sustain life of the bacterium. The complex molecules that are contained in food provide the energy needed by
living organisms to carry out all life functions. These molecules are not useful to the organism unless they are first broken down into smaller, simpler forms through digestion. Digestion involves the hydrolysis (breakdown) of proteins to amino acids, starches to monosaccharides, and fats to fatty acids and glycerol. Unfortunately, hydrolysis at body temperature occurs at a rate that is too slow to be useful to the organism. To speed up (catalyze) the hydrolysis reaction, living organisms produce and use enzymes. Carbohydrate digestion begins in the mouth with an enzyme called salivary amylase. This enzyme is an alpha-amylase whose function is to reduce starch, a complex carbohydrate, to simple sugars. Starch is initially reduced to maltose and then to glucose. The glucose is absorbed by the intestines and used to supply energy for the body.