Protein is a chemical substance that is an organic compound of high molecular weight type. The protein contains over a hundred residues of various amino acids. Each person in his body should contain at least fifteen kilograms of protein.
Proteins can be of several types:
1. Proteins of a simple peptide type. They consist of no more than one hundred amino acid residues.
2. Proteins of the oligopeptide type. They include two to ten amino acid residues in the chain.
3. Proteins of the polypeptide type. They include from ten to one hundred amino acid residues in the chain.
It must also be said that proteins can be in one of four forms of organization:
1. This is the primary form of protein. In this form, the protein is represented by a linear molecule that consists of a sequence of amino acid residues.
2. This is a secondary form of protein. In this form, the protein changes in space, it forms a kind of spiral, fixed by hydrogen bonds.
3. This is a tertiary form of protein. In this form, with the help of various bonds, the helix of a protein molecule bends and folds into a kind of spherical structure, which in chemistry is called a globule.
4. This is a quaternary form of protein. In this case, several protein molecules in the form of globules are fixed to each other through bonds.
When an external effect occurs on a protein, for example, the influence of a factor such as elevated temperature, the protein molecule begins to break down gradually, form after form. But when, finally, the primary structure of the protein is destroyed , it is said that protein hydrolysis has occurred. Hydrolysis of proteins is a process of a kind of destruction of the primary form of a protein molecule. This complex process can occur both in an acidic medium and in an alkaline medium. An obligatory participant in such a natural process as protein hydrolysis in the body is the enzyme - peptidase - hydrolase. Protein hydrolysis is the last step in the breakdown of a protein type molecule. The destruction of a secondary or higher form of a molecule is called denaturation. Denaturation can occur in a reversible and irreversible form. Reversible denaturation occurs when weak bonds in the protein molecule are broken, and irreversible denaturation occurs when complex strong covalent bonds are broken.
Such an important product in our life as milk also consists mainly of protein. Its protein includes three main components:
1. Protein casein. It is found in milk about three percent.
2. Lactobulmin. It is close in composition to the protein found in blood serum. It is found in milk about half a percent.
3. Lactoglobulin. This protein is very useful for immunity. It has immune and antibiotic powers.
Protein in milk can only be in a soluble state, and it is also absorbed by eating ninety-eight percent of it. It plays an important role in the body that consumed it as food. Its main purpose is to participate in the formation of new body cells, especially in young plant and animal organisms, and it also helps to restore old cells.
In milk, including, may contain a certain amount of proteins of whey origin or other similar origin. Such proteins enter the milk from the cells of the mammary gland and, in fact, are vital products of the organism from which this product was taken. Milk protein also contains the most essential amino acid residues, which cannot be synthesized in the body, but in any case are necessary for its subsequent existence and vital activity.