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What are proteins?
Proteins are large organic compounds. They are made up of amino acids arranged in a linear chain and are joined together by peptide bonds. These bonds are joined together between the carboxyl and amino groups. The sequences of amino acids are defined by a gene and are fed in the genetic code. Proteins often associate to achieve stable complexes. Proteins can be classified in to three main classes based on their structures. They are globular proteins, fibrous proteins and membrane proteins.
The globular proteins are usually soluble and most of them are enzymes. The fibrous proteins are purely based on the structure. The membrane proteins often act as a channel for charged molecules and letting it to pass through the cell membrane.
What is the role of protein in human?
The proteins play a vital role in the living organisms. They participate in all the process that takes place within the cells. The proteins are mostly enzymes which catalyze the biochemical reactions. They are the vital enzymes for metabolism. The proteins have also mechanical functions. They are actin and myosin in the muscle and proteins in the cytoskeleton system. The cytoskeleton system forms and maintains the cell shape. The proteins also play a vital role in immune responses, cell signalling and the cell cycle. Protein also plays an important role in animal’s diet, because the animals cannot synthesize the amino acids. They derive from the food and use it in metabolism.
What are the functions of proteins?
Proteins are first broken down in the intestine during digestion by proteases which are a type of enzyme in to smaller polypeptides. These polypeptides provide amino acids for the living organism which includes the essential acids which the organisms cannot synthesize itself. These amino acids and their derivatives are absorbed by the gastrointestinal tract. The absorption is dependent on the source proteins.
The functions of proteins are highly dependent on its molecular structure. These proteins are generally insoluble in water. The proteins are usually structurally large, but in some cases like the enzymes, carriers and antibody, the structure is a bit small. This feature helps in their mobility within the blood and cell fluids. The tertiary and quaternary structures of the enzymes are most important because they enable the enzymes to cause reaction in the intended molecule. For example if a carrier molecule is to carry oxygen, it must be able to stick the oxygen molecule. These are dependent on the structure of the enzyme. The overall function of the proteins is to facilitate the life process.
Proteins are available in meat, egg, grain, legume and dairy products. There are 20 amino acids out of which 12 are synthesized within our body. The remaining 8 are called as the essential amino acids, which we should consume through food.