Protein composition: what do we know about it?

As you know, proteins are a necessary and basic component of any living organism. They are responsible for the metabolism and transformation of energy, which are inextricably linked with virtually all processes of life. The dry matter of the vast majority of tissues and organs of animals and humans, as well as more than 50% of all microorganisms, consist mainly of proteins (from 40% to 50%). In the plant world, their relative weight is smaller than the average, and in the animal - more. At the same time, the chemical composition of proteins for many people is still unknown. Let's once again remember what is inside these high molecular weight natural polymers.

Protein composition

This substance on average contains about 50-55% of carbon, 15-17% of nitrogen, 21-23% of oxygen, and 0.3-2.5% of sulfur. In addition to these basic components, sometimes the composition of proteins includes elements, the specific gravity of which is very insignificant. First of all, it is phosphorus, iron, iodine, copper and some other micro- and macro elements. Curiously, the concentration of nitrogen is the most constant, while the content of other key components can vary. Describing the composition of the protein, it should be noted that it is an irregular polymer built from amino acid residues, the formula of which in the water solution at neutral pH in its most general form can be written as NH3 + CHRCOO-.

Between these "bricks" are connected by an amide bond between the carboxyl and amine groups. In total, about 1,000 different proteins have been detected in nature. This class includes antibodies, enzymes, many hormones and other active biological substances. Surprisingly, with all this diversity, the protein composition can include no more than 30 different amino acids, 20 of which are the most popular. In the human body, only 22 are contained, the rest are simply not digested and are taken out. Eight amino acids from this group are considered irreplaceable. These are leucine, methionine, isoleucine, lysine, phenylalanine, tryptophan, threonine and valine. Their organism can not synthesize on its own, and therefore they require their admission from outside. The rest (taurine, arginine, glycine, carnitine, asparagine, histidine, cysteine, glutamine, alanine, ornithine, tyrosine, proline, serine, cystine), it can quite create independently. Therefore, such amino acids belong to the group of substitutes. Depending on the presence in the protein of the first group, and also on the degree of its assimilation by the body, the protein is divided into full and incomplete. The average daily intake of this substance for a person lies in the range from 1 to 2 grams per kilogram of weight. In this case, people with low mobility should adhere to the lower limit of this range, and wrestlers - the upper one.

How the composition of the protein is studied

To study these substances, the hydrolysis method is mainly used. The protein of interest is heated with dilute hydrochloric acid (6-10 mol / liter) at a temperature of 100 ° C to 1100 ° C. As a result, it breaks up into a mixture of amino acids, from which already isolated individual amino acids. At present, paper, as well as ion-exchange chromatography, is used for the quantitative analysis of the studied protein. There are even special automatic analyzers, which easily determine which amino acids are formed as a result of decay.