Basic information about protein

^Protein

A protein is any of numerous, large, complex, naturally occurring molecules that is composed of one or more chains of amino acids. They are found in all animal and plant tissue as well as in viruses and are necessary for a wide variety of activities, including muscular growth and cell repair.

Proteins are also a functional component of enzymes, hormones, antibodies, etc. they are used for energy only when carbohydrates and fats are not available. An enzyme is any protein that acts as a catalyst in living organisms. A catalyst is a chemical that mediates or speeds up a specific chemical reaction without being destroyed or altered upon completion of the reaction.

Protein is an essential part of the diet of animals. It can be obtained from animal-derived foods such as meat, fish, eggs and milk as well as from some vegetables, particularly beans. Many humans consume excessive amounts of protein, which can result in a variety of health problems.

Proteins were first described in 1838 by the Swedish chemist Jöns Jakob Berzelius, who also created the word from the Greek word prota, which means of primary importance. However, it was not until 1926 that their central role in living organisms was fully recognized, as a result of James B. Sumner showing that the enzyme urease was a protein. The first protein structure, that of myoglobin, the primay oxygen-transporting pigment in muscle tissue, was discovered in 1958 by Max Perutz and Sir John Cowdery Kendrew in 1958, which resulted in their receiving a Nobel Prize in Chemistry.

There is still a great deal to be learned about proteins. One reason for this is their vast numbers: for example, in humans alone there are hundreds of thousands of different proteins, as contrasted with only tens of thousands of genes. And there are differences in proteins according to the species of animal or plant, even among proteins that perform analogous functions. Another reason is that they can be very difficult to work with at the molecular level, in part because they can change their shapes.