About proteins, as a basic element of the human diet, began talking in the XIX century. It was then, they were called "proteins" - from the Greek "protos", which means "first". Proteins are really the "first" in importance for the human body.
We know that all life is built from protein. But the protein itself is built from amino acids. Proteins and amino acids are interrelated, like words and letters. Proteins are polymers, amino acids are monomers. The quality of the protein is determined by its amino acid composition, the quality of the amino acid is its ability to become part of the protein.
Amino acids, which are part of the protein of only 20, in nature there are about 600 varieties. These 20 amino acids create millions of different proteins that differ in quality and effect. As in words, it is important not what letters are in them, but in what order these letters are located, and in the case of proteins: you can meet a variety of proteins with the same amino acid composition, but the order of arrangement of the composite amino acids will be different.
Replaceable and essential amino acids
As we already mentioned, there are 20 amino acids that make up the protein. They are divided into interchangeable, irreplaceable and conditionally replaceable. Irreplaceable amino acids are 8 amines, which we can not synthesize on our own, and therefore must consume them with food. In the world, only plants can synthesize all the amino acids themselves, all the rest have to look for them in food.
We can synthesize 12 amino acids by ourselves. They are formed from other amino acids, as needed. True, for this to happen, we should not have a deficit of irreplaceable amines. Conditionally substitutable are amino acids, which we partly synthesize, partially replenish from food. At illnesses or diseases, infringements of work GASTROINTESTINAL TRACT synthesis process temporarily stops.
When food is consumed, protein is synthesized from amino acids (the body chooses what it needs to spend amines for now), if there is no need for this amino acid, it is delayed in the liver until the first requirement.
Classification of proteins by amino acids
To date, there is no specific unified classification of proteins, primarily because their role is not yet fully understood. However, many are inclined to make the division of proteins, based on the amino acids in its composition. That is, it is a qualitative classification that speaks about the value of protein - whether it contains essential amino acids or not.
The process of protein formation in our body is as follows:
1. We consume protein (animal or vegetable).
2. With the help of gastric juice and pancreatic enzymes, we split it up into amino acids.
3. Amino acids in the intestine are absorbed into the blood and distributed according to the needs of the organism:
- Of these, a protein (already "human") can be immediately created, for example, hemoglobin , enzymes;
- another amino acid may be created, which is currently of interest to the body;
- or if there is no need for amino acids to create proteins, the first will be stored in the liver, before this need arises.
Excess and shortage of amino acids and proteins
Millions of people in the world suffer from a lack of amino acids and proteins. The reason for this is hunger, an unbalanced diet (for example, in the tropics, where the lack of protein in the diet is a deplorable norm), or violations in the body, in which proteins are not digested, or protein is not synthesized from amino acids. The most typical manifestation of protein deficiency is:
- inadequate growth and development of the organism;
- anemia;
- lack of digestive enzymes;
- lowered immunity.
However, the excess protein is no less pleasant to the body. This leads to the following diseases:
- cancer;
- arthritis;
- diabetes;
- cardiovascular diseases.