Other than water, proteins are the most abundant type of chemical in the human body. Proteins play many vital roles in the human body, including providing structure and strength to cells and tissues, controlling biochemical reactions and aiding the immune system. Metabolism is regulated by proteins, as are hormones and the various activities they control. Proteins also regulate cell division, which acts to replenish aged or damaged cells to ensure a constant supply of healthy cells.
Proteins are the main components of many structures in the body. They are part of the outer membrane of all cells in the human body. Proteins are also abundant in hair, skin, muscles and most other organs and tissues. Proteins often act to strengthen these structures. Proteins working together can allow movement within the body, such as contraction of muscles and movement of food through the digestive system.
Driving Biochemical Reactions
Enzymes are a specific type of protein that enable biochemical reactions in the body. These reactions may occur without enzymes, but enzymes make the reactions happen faster. Many different types of reactions in the body are driven by the action of enzymes, which affect breathing, digestion and nervous system functions. Enzymes are also critical to metabolism, a series of biochemical reactions that turn food into energy.
Some hormones are also proteins. Hormones regulate growth and development and are crucial during puberty. They affect fertility by regulating the menstrual cycle and production of sperm. Hormones also regulate muscle mass, hair growth, metabolism and even mood. Hormone levels change throughout life and help regulate the aging process, from childhood to adulthood to the later stages of life.
Regulation of Cell Division
Proteins regulate cell division, an important process for replenishing aged or damaged cells. Over time, cells can become damaged from exposure to the sun or other harmful substances in the environment. These cells undergo a natural process of cell death and need to be replaced. This is accomplished by division of healthy cells into two copies, which is regulated by proteins called growth factors. Failure of proteins to properly regulate the division process can cause tumor growth and cancer.
Immune System Actions
Antibodies are another type of protein essential to human health. Antibodies are a major component of the immune system and help fight infections caused by bacteria and viruses. The immune system produces many different antibodies, each with a slightly different structure that allows it to recognize a specific type of bacteria, virus or other type of invading organism. Once an antibody recognizes and binds to an invading germ, it signals the immune system to destroy the invader.