Proteins

Proteins were identified in a separate class of biological molecules in the XVIII century as a result of the French chemist Antoine Furkrua and other scientists, which was noted feature of proteins coagulate (denature), under the influence of heat or acids. At the time, were studied proteins such as albumin ( «glair»), fibrin (a blood protein) and gluten from the grains of wheat. Dutch chemist Gerrit Mulder carried out an analysis of proteins and put forward a hypothesis that nearly all proteins have a similar empirical formula. The term «Protein» to refer to these molecules was proposed in 1838 Muldera Officer Jacob Bertseliusom. Mulder also identified the products of destruction of proteins - amino acids and one of them (leucine) is almost precisely defined molecular weight - 131 Dalton. In 1836 Mulder proposed the first model of the chemical structure of proteins. Based on the theory of radicals, he formulated the concept of minimal structural unit of protein, C16H24N4O5, which was named the protein (Pr), a theory - the theory of protein. As the accumulation of new data on protein theory has been criticized, but before the end of 1850 remained generally recognized.

By the end of the XIX century, it was investigated, most of amino acids, which are part of the protein. In 1894, German physiologist Albrecht Kossel put forward the theory that it is amino acids are the basic building blocks of proteins. At the beginning of XX century German chemist Emil Fischer experimentally proved that proteins are composed of amino acid residues connected by peptide bonds. He undertook a first analysis of amino acid sequence of the protein and explain the phenomenon of proteolysis

However, the central role of proteins in organisms, was not recognized until 1926, when the American chemist James Sumner (later - a Nobel laureate) demonstrated that the enzyme urease was the protein.

Examine the protein prevented the complexity of their selection. Therefore, the first study of proteins were carried out using the polypeptides, which could be cleaned up in large numbers, ie, blood proteins, eggs, various toxins and digestive / metabolic enzymes, which can be allocated in the slaughter of livestock. In late 1950 the company Armour Hot Dog Co was able to clear kilogram bull pancreatic ribonukleazy A, which was the pilot sites for many scientists.

The idea that the secondary structure of proteins is formed as a result of hydrogen bonds between amino acids, was William Astberi in 1933, but Laynus Poling is considered the first scientist who was able to successfully predict the secondary structure of proteins. Later, Walter Kauzman, drawing on the work of Kai Linderstrem-Lang, made a significant contribution to the understanding of the laws of education tertiary structure of proteins and the role of hydrophobic interactions. In 1949, Fred Senger identified amino acid sequence of insulin, demonstrating in a way that the protein - is the linear polymers of amino acids, but not the extensive (as in some sugar) chain colloids or tsikloly. The first structures of proteins, based on the diffraction of X-rays at the level of individual atoms have been received in the 1960's and with the help of NMR in the 1980's. In 2006, the Data Bank proteins (Protein Data Bank) contains approximately 40 000 protein structures.

In the XXI century, the study of proteins shifted to a qualitatively new level, where we study not only the individual purified proteins, but also a simultaneous change in the quantity and posttranslyatsionnyh versions of a large number of proteins specific cells, tissues or organisms. This area is called biochemistry proteomics. Using bioinformatics techniques has become possible not only to process the data, X-ray structural analysis, but also to predict protein structure based on its amino acid sequence. Currently krioelektronnaya microscopy of large protein complexes, and the prediction of small proteins and domains of large proteins by means of computer programs for accuracy approaching the resolution of structures at the atomic level.