high organic material, consisting of connected chain peptide bond amino acids. In living organisms, amino acid composition of proteins is determined by genetic code, in the synthesis of the most used 20 standard amino acids. Many combinations of them offer a great variety of properties of molecules. In addition, the amino acids within the protein are often subjected to posttranslyatsionnym modifications that may occur before the protein starts to perform its function, and while it «work» in the cell. Often, a few molecules of living organisms, proteins are complex systems, such as the photosynthetic complex.
The functions of proteins in cells of living organisms are more varied than the other functions of biopolymers - polysaccharides and DNA. For example, proteins, enzymes catalyze the course of the biochemical reactions and plays an important role in metabolism. Some proteins serve a structural or mechanical function, forming a cytoskeleton that supports the form of cells. Also, proteins play an important role in cell signaling systems, as immune response and cell cycle.
Proteins - an important part of food animals and humans because their bodies can not synthesized all the necessary amino acids and some of them come from protein foods. In the digestive enzymes destroy the proteins to amino acids, which are used in the biosynthesis of protein organism or subject to further decay to generate energy.
Determination of amino acid sequence of the first protein - insulin - the method of sequencing proteins brought Frederick Sengeru the Nobel Prize in 1958. The first three-dimensional structure of proteins and hemoglobin mioglobina were obtained by the diffraction of X-rays, respectively, Maxim Perutsem and Kendra John in 1958, which in 1962 they received the Nobel Prize for chemistry.