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What Are the Functions of Protein in the Human Body?

author image Noelle Thompson
Noelle Thompson has extensive experience with health and scientific research, including in the biotechnology/pharmaceutical industry. She graduated from the University of California, Santa Barbara, with a B.S. in cell and developmental biology. Thompson then went on to earn a Ph.D. in biological chemistry, with an emphasis on stem cell biology, from the University of California, Irvine.
What Are the Functions of Protein in the Human Body?
3D of cells. Photo Credit: DTKUTOO/iStock/Getty Images

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.

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Structural Functions

3D of human cells.
3D of human cells. Photo Credit: tagota/iStock/Getty Images

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

Metabolism turns food into energy.
Metabolism turns food into energy. Photo Credit: george tsartsianidis/iStock/Getty Images

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.

Hormonal Regulation

Hormones. Photo Credit: moodboard/moodboard/Getty Images

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

Cancer cells.
Cancer cells. Photo Credit: Duncan Smith/Photodisc/Getty Images

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

Microscopic view of bacteria.
Microscopic view of bacteria. Photo Credit: Duncan Smith/Photodisc/Getty Images

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.

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