Sources of protein (protein)
Proteins (proteins, polypeptides) are high-molecular organic substances consisting of alpha-amino acids linked in a chain by a peptide bond. In living organisms, the amino acid composition of proteins is determined by the genetic code, in the synthesis, in most cases, 20 standard amino acids are used. A lot of their combinations create protein molecules with a wide variety of properties. In addition, amino acid residues in the protein are often subjected to post-translational modifications, which may occur before the protein begins to perform its function, and during its "work" in the cell. Often in living organisms several molecules of different proteins form complex complexes, for example, a photosynthetic complex.
The functions of proteins in the cells of living organisms are more diverse than those of other biopolymers - polysaccharides and DNA. Thus, enzyme proteins catalyze the course of biochemical reactions and play an important role in the metabolism. Some proteins perform a structural or mechanical function, forming a cytoskeleton that supports the shape of cells. Also, proteins play a key role in the signaling systems of cells, with an immune response and in the cell cycle.
Proteins are an important part of the nutrition of animals and humans (the main sources are meat, poultry, fish, milk, nuts, beans, cereals, to a lesser extent: vegetables, fruits, berries and mushrooms), because in their organisms all necessary amino acids can not be synthesized part should come with protein food. In the process of digestion, enzymes destroy consumed proteins to amino acids that are used for the biosynthesis of the body's own proteins or are further decomposed to generate energy.
Determination of the amino acid sequence of the first protein - insulin - by protein sequencing brought Frederic Senger the Nobel Prize in Chemistry in 1958. The first three-dimensional structures of hemoglobin and myoglobin proteins were obtained by the X-ray diffraction method, respectively, by Max Peruets and John Kendry in the late 1950s, for which in 1962 they received the Nobel Prize in Chemistry.
Sports nutrition is a special group of food products, produced primarily for people who are active in life, engaged in sports and fitness. The intake of sports nutrition is primarily aimed at improving sports results, increasing strength and endurance, strengthening health, increasing muscle volume, normalizing metabolism, achieving optimal body weight and generally improving quality and longevity. Sports nutrition is included in the category of supplements, since its correct use is an addition to the basic diet consisting of conventional products, and not a complete replacement. The vast majority of sports nutrition products have nothing to do with doping.
Crystals of various proteins grown on the space station "Mir" and during the space shuttle flights of NASA. Highly purified proteins form crystals at low temperature, which are used to study the spatial structure of this protein.