Proteins are highly complex substance present in all living organisms. The term protein was first discovered by J. Berzelius. Proteins contain a complex nitrogen-rich organic substance bonded through peptide bonds and is made up of the molecules of carbon, hydrogen, oxygen and nitrogen.
Along with this there are some proteins in which sulphur, zinc, phosphorus etc. are found in very small amounts. It nurtures the muscles within our body. The rich source of vital proteins is milk, egg, meat, fish, rice, cheese, pulses, nuts etc.
Types of proteins
There are mainly three types of proteins simple proteins, conjugated proteins and the derived proteins.
Simple proteins are made up of only amino acids are called simple proteins like albumin, globumins, prolamins, gluremins etc. Hormones and enzymes are examples of simple and derived proteins.
When another group in a chain of amino acids is joined by a peptide bond, a conjugated protein is formed. Such as haemoglobin, cytochrome heparin, keratin, mucin etc.
Derived proteins are proteins that have more than one substance in a chain of amino acids joined by peptide bonds. This protein is responsible for the strengthening of our muscles of the body. Like insulin, fibrin etc.
What are the building blocks of proteins?
The building blocks of proteins are α-amino acids, small molecules that contain a carboxylic acid and an amino group. There are 20 types of amino acids within the body, some of which are essential and some are nonessential. Nonessential amino acids can be synthesized by the body, including vitamin B6 plus alpha keto acids. Essential amino acids are not synthesized by the body; hence we need to have variety in our diet in order to fulfil the necessary requirement of the protein in the body.
Humans who are carnivores get 20 amino acids at once when they eat the meat of other animals. This type of protein is called class 1 protein. Such individuals do not need to have variety in their diet. On the other hand, people who are vegetarians do not get 20 amino acids from any one vegetable at a time. Therefore this type of protein is called class 2 protein. Such individuals need to have variety of protein rich food in their diet.
Proteins are the main components of the protoplasm and are involved in physiological growth, repair and various biological functions. Friends, do you know how much energy our body gets from 1 gram of protein? Our body gets about 4.2 calories of energy from 1 gram of protein.
Role of Proteins within the body
Protein is a major source of energy in the body. If the body consumes more protein than is required for the maintenance of body tissues and other essential functions, the body will start using it for energy. If it is not needed due to adequate intake of other energy sources such as carbohydrates, protein is used to make fat and to form fat cells.
Repair and Maintenance
Protein is considered to be an important part of the body building. That’s because protein is important in the growth and repair of the body as well as the maintenance of body tissues. Hair, skin, eyes, muscles and other organs are all made up of protein. This is the reason why a child requires more proteins intake than adults. More protein is needed per pound of weight as they are growing and developing new protein tissue.
Protein also aids in the production of certain hormones. Hormones help control body functions that involve the interaction of many organs. Insulin is an example of a hormone that regulates blood sugar in the body. Secretin is another example of a protein hormone. This substance aids in the simple digestion process by stimulating the pancreas and intestine to make the necessary digestive juices.
Proteins also make antibodies in the body that help prevent disease. These proteins help to identify and destroy antigens such as bacteria and viruses. They often work together with other immune system cells. For example, these antibodies recognize antigens and then engulf them until they can be destroyed by white blood cells.
Enzymes are also a protein that increases the rate of chemical reactions within the body. In fact, most of the essential chemical reactions in the body would not be possible without enzymes. For example, one enzyme serves as an aid in the digestion of large protein, carbohydrate and fat molecules into smaller molecules, while the other aids in the formation of DNA.
Transportation and storage of molecules
Transport proteins are a key element for the transportation of some essential molecules within the body. For example, haemoglobin is one of the carrier proteins that transports oxygen throughout the body. Proteins are sometimes also used to assemble certain molecules. Ferritin proteins combine with iron for storage in the liver.