Sources of protein (protein)
Proteins (proteins, polypeptides) - high-molecular organic substances consisting of alpha-amino acids, connected 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. Many of their combinations create protein molecules with a wide variety of properties. In addition, amino acid residues in the composition of the protein are often subjected to post-translational modifications that can 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, the photosynthetic complex.
The functions of proteins in the cells of living organisms are more diverse than the functions of other biopolymers - polysaccharides and DNA. Thus, enzyme proteins catalyze the course of biochemical reactions and play an important role in metabolism. Some proteins perform a structural or mechanical function, forming a cytoskeleton that supports cell shape. Proteins also play a key role in cell signaling systems, in the immune response and in the cell cycle.
Proteins are an important part of animal and human nutrition (main sources: meat, poultry, fish, milk, nuts, legumes, grains; to a lesser extent: vegetables, fruits, berries and mushrooms), since all necessary amino acids and part should come from protein foods. In the process of digestion, enzymes destroy the consumed proteins to amino acids, which are used for the biosynthesis of the body's own proteins or undergo further decomposition for energy.
Determining the amino acid sequence of the first protein, insulin, by protein sequencing brought the Nobel Prize in Chemistry to Frederick Senger in 1958. The first three-dimensional structures of hemoglobin and myoglobin proteins were obtained by X-ray diffraction, respectively, by Max Perutz and John Kendru 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 mainly for people leading an active lifestyle engaged in sports and fitness. Acceptance of sports nutrition is aimed primarily at improving athletic performance, increasing strength and endurance, improving health, increasing muscle volume, normalizing metabolism, achieving optimal body weight and, in general, increasing quality and longevity. Sports nutrition is included in the category of supplements, as its correct use is an addition to the basic diet, which consists of ordinary products, and not their full replacement. The vast majority of sports nutrition products have nothing to do with doping.
Crystals of various proteins grown on the Mir space station and during flights of NASA shuttles. High-purity proteins form crystals at low temperatures, which are used to study the spatial structure of this protein.