The Elmhurst College Virtual Chembook defines an enzyme as a protein that speeds up chemical reactions and produces chemical products. The human body could not function properly without enzymes, as these proteins assist in chemical reactions ranging from the metabolism of proteins to the replication of deoxyribonucleic acid--more commonly known as DNA--in cells.
Gastric Enzymes
The organs of the digestive system break down large food molecules and make them easier to absorb or pass out of the system in the form of waste. During the process of digestion, digestive enzymes mix with food to make it easier to break down the particles. The stomach produces several enzymes known as gastric enzymes. Pepsin breaks down large protein molecules into smaller amino acid molecules, according to Clinton Community College. Gastric amylase breaks down starches. Gelatinase breaks down specific types of collagen and gelatin found in meats.
Intestinal Enzymes
The juice produced by the ileum and jejunum of the intestine contains several enzymes to aid in the digestive process. Maltase converts maltose into glucose, which the body uses for energy. Sucrase breaks sucrose molecules into fructose and glucose. Lactase breaks down the lactose found in dairy products and other foods, as explained by Austin Peay State University. This enzyme turns the lactose into galactose and glucose. Isomaltase breaks down both isomaltose and maltose.
Pancreatic Enzymes
The pancreas produces several enzymes that break down food molecules. Chymotrypsin breaks proteins into molecules known as aromatic amino acids. Pancreatic amylase breaks down most carbohydrates, with the exception of cellulose. Humans do not have an enzyme available to digest this type of starch, according to the Polymer Science Learning Center. Trypsin breaks proteins into basic amino acid molecules. Steapsin breaks down the triglycerides found in fatty foods. The byproducts of this process include glycerol and fatty acids.
DNA Replication Enzymes
DNA contains instructions that help determine the characteristics of a human being. Found in the nucleus, or control center of a cell, DNA molecules consist of a sugar called deoxyribose, a phosphate group made of one atom of phosphorus and four atoms of oxygen, and a base that contains nitrogen. DNA replicates itself in order to create new proteins and participate in other processes. In order to replicate itself properly, DNA relies on enzymes that participate in the replication process. Helicase helps the DNA strands unwind so replication can occur, as explained by Rensselaer Polytechnic Institute. When the two strands unwind, Y-shaped forks appear. These forks provide the site of DNA copying. DNA polymerase III helps the base units of DNA bond together.
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