Functions of Proteins

Proteins

Proteins are large, complex molecules that are critical for the normal functioning of the human body. They are essential for the structure, function, and regulation of the body’s tissues and organs. Proteins are made up of hundreds of smaller units called amino acids that are attached to one another by peptide bonds, forming a long chain.

Functions of proteins

Proteins are of primary importance to the continuing functioning of life on Earth. Proteins catalyze the vast majority of chemical reactions that occur in the cell. They provide many of the structural elements of a cell, and they help to bind cells together into tissues.

1.                  Growth and Maintenance

Protein is termed as the building block of the body. They make up the hair, nails, muscles etc. Protein is necessary to the immune response that helps to heal the tiny muscle tears. It is vital in the maintenance of body tissue, including development and repair.

 

2.                  Provides Structure

Some proteins are fibrous and provide cells and tissues with stiffness and rigidity. These proteins include keratin,collagen and elastin. Keratin is a structural protein that is found in your skin, hair and nails. Collagen is the structural protein of bones, tendons, ligaments and skin.

3.                  Causes Biochemical Reactions

Enzymes are proteins that allow key chemical reactions to take place within the body and aid thousands of biochemical reactions within and outside of cells. They play a role in many activities such as muscle contraction and relaxation, and nerve impulse transmissions. A well-known example of an enzyme is lactase, which facilitates the metabolism of lactose, or milk sugar. Bodily functions that depend on enzymes include:

• Digestion
• Energy production
• Blood clotting
• Muscle contraction

 

4.                  Muscle Contraction

 

Actin and Myosin are two specialized types of filament protein present in your muscle. When stimulated by a signal from the central nervous system, these two proteins act in unison to shorten in length, causing your muscle to contract.

5.                  Transport

 

Protein is a major element in transportation of certain molecules including nutrients like vitamins or minerals, blood sugar, cholesterol.  For example, hemoglobin is a protein that transports oxygen throughout the body and carbon dioxide back to the lungs for excretion from the body. Glucose transporters (GLUT) move glucose to cells, while lipoproteins transport cholesterol and other fats in blood.

6.                  Hormone Production

 

Hormones are chemicals produced by glands in one part of the body that help coordinate activities and communicate with other areas. Many hormones are protein in nature that control growth and metabolic activities of the body. Hormonal proteins, like insulin and oxytocin, play vital roles like controlling blood sugar concentration and stimulating contractions during childbirth. Secretin assists in the digestive process by stimulating the pancreas and the intestine to create necessary digestive juices.

7.                  Immune Function

 

Antibodies are specialized protein configurations that provide a specific immune defense against invaders. They are produced by the body once it's exposed to specific antigens such as bacteria, viruses and fungi. Complement proteins support the immune system as a second line of defense. They can create holes in bacterial walls, promote inflammation which attracts macrophages that destroy invading organisms, and attach to the foreign substances.

8.                  Storage 

Proteins have storage roles to store various nutrients. For example, Ferritin is a storage protein that stores iron in the spleen and liver. Casein stores protein in milk that helps babies to grow.

9.                  Antibodies

Protein forms antibodies that help prevent infection, illness and disease. These proteins identify and assist in destroying antigens such as bacteria and viruses. They often work in conjunction with the other immune system cells. For example, these antibodies identify and then surround antigens in order to keep them contained until they can be destroyed by white blood cells.

10.              Acts as a Messenger

Some proteins are hormones, which are chemical messengers that aid communication between the cells, tissues and organs. They’re made and secreted by endocrine tissues or glands and then transported in the blood to their target tissues or organs where they bind to protein receptors on the cell surface. Protein and polypeptides make up most of body’s hormones. Some examples include Insulin signals the uptake of glucose or sugar into the cell, Glucagon signals the breakdown of stored glucose in the liver, hGH (human growth hormone) stimulates the growth of various tissues, including bone, ADH (antidiuretic hormone) signals the kidneys to reabsorb water and ACTH (adrenocorticotropic hormone) stimulates the release of cortisol, a key factor in metabolism.

11.              Provides Energy

Protein is broken down into amino acids during digestion and provides four calories per gram. Protein is a major source of energy. Body can use protein for its energy needs when carbohydrates are depleted. When needed, proteins degrade into their component amino acids, which are then oxidized in the same process as glucose to create energy.  

12.              Maintains Proper pH

Protein plays a vital role in regulating the concentrations of acids and bases in blood and other bodily fluids. A variety of buffering systems allows bodily fluids to maintain normal pH ranges. Proteins act as a buffer system, helping the body maintain proper pH values of the blood and other bodily fluids. An example is hemoglobin, a protein that makes up red blood cells. Hemoglobin binds small amounts of acid, helping to maintain the normal pH value of blood.

13.              Balances Fluids

Proteins regulate body processes to maintain fluid balance. Albumin and globulin are proteins in blood that help maintain body’s fluid balance by attracting and retaining water.

Summery 

Protein has many roles in the body. It helps repair and build body’s tissues, allows metabolic reactions to take place and coordinates bodily functions. In addition to providing the body with a structural framework, proteins also maintain proper pH and fluid balance. Some proteins act as contractile elements to make movement possible. Finally, they keep the immune system strong, transport and store nutrients and can act as an energy source, if needed.

Collectively, these functions make protein one of the most important nutrients for human health.