Each of us at least once in his life thought about his diet. For example, what daily norm of various substances necessary for the body comes to us with food? What amino acids do we need and why? Today, of course, we will not talk about proper nutrition in general, since this is not enough for one or even a dozen articles. We will tell only about one substance, which is undoubtedly very important for the body. This is the amino acid histidine. Its chemical name sounds complicated - L-2-amino-3- (1H-imidazol-4-yl) propanoic acid. But first things first.
What is an amino acid?
Before discussing the properties of histidine and its role in the body, we will understand the concept of “amino acid”. Those who were fond of sports heard about these substances. An amino acid is an organic compound having two main functional groups that make it special: it is the amino group —NH 2 and the so-called carboxyl group —COOH.
The first is responsible for the basic properties of this unusual class of compounds. Thanks to nitrogen and its pair of electrons, an amino acid can form positively charged ions. In this case, the amino group turns into such an ion: -NH 3 + .
The second functional group is responsible for acidic properties. It is able to give off a proton, turning into the anion -COO - . This phenomenon makes it possible to form salts from the side of the carboxyl group.
Thus, an amino acid has two parts, each of which is capable of forming salts. One of them provides the properties of acids to these compounds, and the other provides bases. In general terms, an amino acid can be represented as follows: NH 2 —CH (R) —COOH. The letter R should be understood here as a "radical", that is, any organic particle consisting of functional groups and a carbon skeleton and capable of forming a bond (or bonds) with the base of an amino acid molecule.
As a rule, even those who are not familiar with pharmacology and were not fond of sports, at least once heard, at least from advertising, that we need amino acids and are very useful. Let's see what functions they perform in the body and why you need to get them in the required norm from food.
The functions of amino acids in the body
As you know, we are all made up of proteins, fats and carbohydrates. And we also eat them to maintain our vitality. But in the subject of this article, we are only interested in proteins. These are huge molecules that perform completely different and very important functions in our body: transporting substances, creating new cells, enhancing the connections between brain neurons.
We started talking about proteins for a reason. The fact is that all such substances are composed of amino acids, which include histidine. The formula of even the simplest protein has at least a dozen amino acids linked in a polypeptide chain. Each of them has its own structure and form, which allows it to perform the function for which it was created by nature.
Histidine
The formula of any amino acid includes, as we have already found out, at least two functional groups and a carbon skeleton connecting them. That is why the difference between all amino acids (of which, by the way, several million have already been found) consists in the length of the carbon bridge between the two groups and in the structure of the radical attached to it.
The topic of our article is one of the amino acids - histidine. The formula of this essential acid is not simple. In the main carbon chain between two functional groups we see only one carbon atom. In fact, all irreplaceable proteinogenic (capable of creating proteins) amino acids also have only one carbon atom in this chain. In addition, histidine has a complex radical structure, including a cycle. Above you can see what histidine is. The formula, the structural feature of which is a heterocycle (the inclusion of any other atoms other than carbon), is actually not the most complex substance.
So, once we have analyzed the basic concepts, we will move on to the reactions that can be carried out with histidine.
Chemical properties
The reactions that this amino acid enters are very few. In addition to reactions with acids and bases, it enters into a biuret reaction, forming colored products. In addition, histidine, the formula of which includes imidazole residues, can interact with sulfanilic acid in the Pauli reaction.
Conclusion
Perhaps, we have sorted out all the main details. We hope that the article was useful to you and gave you new knowledge.