Protein Functions in the Body
- Structure
- Catalysis
- Movement
- Transport
- Communication
- Protection
- Regulation of fluid balance and pH
Structure: Proteins provide most of the structural materials in the body, being constituents of the muscles, skin, bones, hair and fingernails. Example: collagen is a structural protein that forms a supporting matrix in bones, teeth, ligaments and tendons. Proteins are also important structural components of cell membranes and organelles
Catalysis: Enzymes (most of which are protein) function as biological catalysts, and speed up chemical reactions that occur in our body. Example: Pepsin digests proteins in the small intestine. Analogy: Consider everything it takes to prepare a meal. Chemical reactions (like meals) will not occur readily without enzymes (chefs) to arrange the molecules in the correct positions
Movement: Some proteins have contractile properties muscles and ligaments to move various parts of the body. Example: Actin and myosin in muscle, make up much of the machinery needed to contract muscles, this is why protein deficiency may cause muscle wasting and weakness
Transport: transport proteins involved in the movement of substances across cell membranes and within the circulatory system. Example: glucose transporters which move glucose from blood to tissues.
Communication: Protein hormones, and cell-signaling proteins regulate biological processes. Example: Insulin and glucagon regulate blood glucose
Protection: Skin proteins and immune proteins. Skin is the first barrier against infection or injury. Foreign particles on the skin such as dirt and bacteria can not penetrate. If skin is broken, and blood vessels are injured, blood clotting proteins help prevent too much blood from being lost. If foreign material does get in, antibodies, which are immune system proteins help destroy it.
Regulation of fluid balance: Proteins, via the process of osmosis, regulate the distribution of fluid in the body's various compartments. Example: Albumin is a major regulator of fluid balance inthe circulatory system
Regulation of pH: The chemical reactions of metabolism require a certain pH (acidity) to function properly. Proteins that readily take up and release Hydrogen ions (H+) mainatin normal (relatively neutral) pH of the body. Example: Hemoglobin is an important regulator of blood pH