Proteins are molecules that build amino acids.
The combination of two amino acids builds a dipeptide, the combination of three forms a tripeptide, etc.
Theoretically, if a molecule is made up of a maximum of 20 amino acids, it is called an oligopeptide. If it is higher and reaches a maximum of 100 amino acids, it is a polypeptide. The greater the amount of amino acids means that the protein is referred to. However, this is a conventional classification, thanks to which we can understand even this work, because it is known that there are proteins with fewer amino acids (eg insulin, which builds 51 amino acids).
Starting from the beginning, each amino acid is made of a carbon atom, which is located in the central part, covalently bonded to it is a hydrogen atom and an amino group (Nh2), a carboxyl group (COOH) and a characteristic for each amino acid substituent, so-called. The radical is conventionally marked with the letter Rrys.1. The substituent is referred to as the amino acid side chain (remember this, because the amino acid radicals affect the catalytic functions of the enzymes).
Amino acids react with bases and with acids. They occur in the form of an inert ion, acidic form and alkaline (depending on ph). Amino acids, except for glycine, form optical L or D optical isomers. Our organisms build only the left-handed ones, i.e. with the L form.
Amino acids can be divided into proteogenic (building proteins) and non-proteogenic (non-protein building). The first one can be divided into endo and exogenous. Endogenous amino acids are those that the body is capable of synthesizing. On the other hand, exogenous ones are those that the body can not synthesise and should be supplied from food.
Let’s move to the construction of protein. These structures are divided into structures, their number is 4. As mentioned earlier, proteins build proteogenic amino acids. Their combination is possible due to the formation of covalent bonds of the peptide type between the carboxyl group (COOH) of one amino acid with the amino group (NH2) of the other.
The primary structure is in the simple language the order of the amino acid linkage, or the sequence of their arrangement. This structure determines the properties of the protein. Its arrangement in space determines the structure of a higher order. And so we go to the next one
This structure can be divided into two models: alpha-helix and beta-harmonica.
Both of these structures are stabilized by hydrogen bonds formed as a result of the affinity of hydrogen atoms to nitrogen or oxygen atoms.
The first one resembles a twisted cylinder, the walls of which are built by peptides and radicals protruding outside. The latter, however, resembles the appearance of long folded pieces of paper that arise from the twists of the bonds of radicals.
This, on the other hand, is a secondary structure folded into a depth. It is stabilized by hydrogen bonds, sulphide bridges, van der Waals interactions.
A quaternary structure is one that consists of a combination of several protein subunits. This structure stabilizes bonds and interactions of the same type as the tertiary structure.
On the occasion of the discussed construction, I will mention protein denaturation.
Protein denaturation is the disintegration, disruption of the secondary stabilizing structure and the tertiary protein scratch.7. Many people ask the question whether boiling, for example, a hen egg in which protein denatures causes its spoiling. Well, denaturation only causes the disintegration of structures, but amino acids, the protein is still available to our body. It loses only its properties (given by given structures), which for us is not important, because it will be digested to individual amino acids. However, protein denaturation facilitates its digestion. Protein renaturation, however, only occurs in laboratories and, as the name suggests, it is a process contrary to the one previously described.
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