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. Many 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 can occur both before the protein begins to fulfill 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 the functions of other biopolymers - polysaccharides and DNA. So, protein enzymes 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 maintains the shape of the cells. 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), because all the necessary amino acids and part should come with protein food. In the process of digestion, enzymes break down the consumed proteins into amino acids, which are used for biosynthesis of the body’s own proteins or undergo further decomposition for energy.
Determination of the amino acid sequence of the first protein - insulin - by protein sequencing brought Frederick Sanger the Nobel Prize in Chemistry in 1958. The first three-dimensional structures of hemoglobin and myoglobin proteins were obtained by X-ray diffraction, respectively, by Max Perutz and John Kendrew in the late 1950s, for which they received the Nobel Prize in Chemistry in 1962.
Sports nutrition is a special group of food products produced primarily for people with an active lifestyle, involved in sports and fitness. The intake of sports nutrition is primarily aimed at improving athletic performance, increasing strength and endurance, improving health, increasing muscle volume, normalizing metabolism, achieving optimal body weight, and generally increasing quality and life expectancy. Sports nutrition belongs to the category of supplements, since its proper use is an addition to the main diet, consisting of ordinary products, and not their complete 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 NASA's space shuttle flights. Highly purified proteins at low temperature form crystals that are used to study the spatial structure of this protein.