Proteins are the complex organic matter consisting of amino acids. Depending on structure of protein, the amino acids which are its part also functions differ.
It is difficult to overestimate a problem of proteins. They act also as construction material, hormones and enzymes have proteinaceous structure. Quite often molecules of inorganic substances — zinc, phosphorus, iron, etc. are a part of proteins.
Proteins consist of amino acids
It is standardly accepted to call only 20 amino acids which are a part of proteins, but them it is known today and more than 200 are revealed. A part of proteins can synthesize an organism itself as can synthesize amino acids, and a part can receive only from the outside, such amino acids are called irreplaceable. At the same time the interesting fact — plants in this plan are more perfect as they are capable to synthesize all necessary amino acids. Amino acids in turn are more plain organic compounds which contain at the same time both carboxyl and aminny group. And amino acids define composition of protein, its structure and functions.
Depending on the amino-acid list of a squirrel are divided into simple and difficult, full and defective. Simple call proteins as a part of which there are only amino acids, and difficult in what there is not amino-acid component. Full-fledged proteins contain all set of amino acids, and as a part of defective a part of amino acids is absent.
Spatial structure of protein
The protein molecule very difficult, it is the largest of all existing molecules. And in expanded form it cannot exist therefore the proteinaceous chain is exposed to laying and acquires a certain structure. In total divide 4 levels of the organization of a proteinaceous molecule.
- The amino-acid remains are consistently located in a chain. Communication between them peptide. In fact it is the developed tape. Properties of protein, so, and its functions depend on primary structure. So, only 10 amino acids allow to receive 10 in the 20th degree of options, and having 20 amino acids the quantity of options repeatedly increases. And quite often conducts damages to a molecule of protein, change of only one amino acid or its location to function loss. So, protein hemoglobin loses ability to transport oxygen if to replace in a B-subunit of the sixth glutamic acid with valine. Such change is fraught with development by serpovidnokletochny anemia.
- Secondary structure. For bigger compactness the proteinaceous tape begins to be twisted in a spiral and reminds the stretched spring. To set structure hydrogen communication between molecule rounds is used. They are weaker than peptide communication, but due to repeated repetitions the hydrogen communications reliably connect rounds of a proteinaceous molecule, give it rigidity and stability. A part of proteins has only secondary structure. The keratin, collagen and fibroin belong to them.
- Tertiary structure. More difficult molecules have it, at this level there is a laying in globula, in other words in a ball. Stabilization happens at the expense of at once several types of chemical bonds: hydrogen, disulfide, ionic. At this level there are hormones, enzymes, antibodies.
- Quarternary structure. The most difficult is also characteristic of complex proteins. Such proteinaceous molecule is formed of several globul at once. Except standard chemical bonds also electrostatic interaction is used.
Properties and functions of proteins
The amino-acid structure and structure of a molecule define its properties, and, the tasks which as a result are carried out. And they more than are enough.
- Construction function. Cellular and extracellular structures consist of proteins: hair, tendons, cellular membranes. And for this reason the lack of proteinaceous food leads to delay of growth and loss of muscle bulk. The organism builds itself of proteins.
- Proteinaceous molecules deliver molecules of other substances, hormones, etc. The most striking example — a hemoglobin molecule. It at the expense of chemical bonds holds a molecule of oxygen and can give it to other cages, taking away at the same time carbonic acid molecules. That is in fact transports them.
- Regulatory function lies on proteins-hormones. So, insulin regulates glucose level in blood and actively participates in carbohydrate exchange. Damages of a molecule of insulin lead to diabetes — the organism cannot acquire glucose or carries out it defectively.
- Protective function of proteins. It antibodies. They are capable to distinguish, connect and neutralize alien cages. At autoimmune diseases, for example, protective proteins do not distinguish others cages from the and attack healthy cells of an organism. And decrease in immunity is caused by weak reaction of protective proteins to alien agents. For this cause of infringement of food often lead also to deterioration in the state of health.
- Motive function. Reduction of muscles is caused by availability of proteins too. So, we move only thanks to actin and myosin.
- Alarm function. The membrane of each cage has molecules of proteins which can change the structure depending on environmental conditions. Quite so the cage receives a certain signal on a certain action.
- The reserving function. Some substances in an organism can be temporarily not necessary, but it is not an occasion to remove them to the external environment. There are squirrels who keep them. Iron, for example, is not removed from an organism, and forms a complex with protein-ferritinom.
- Proteins are extremely seldom used as energy, for this purpose there are fats and carbohydrates, but if they are absent, protein at first breaks up to amino acids, and further to water, carbon dioxide and ammonia. If it is simple - the organism consumes itself.
- Catalytic function. These are enzymes. They can change the speed of chemical reaction, most often towards its acceleration. Without them we could not digest food, for example. Process would go inadmissibly long. And at gastrointestinal diseases quite often there is an enzymatic insufficiency — they are appointed in the form of tablets.
These are the main functions of proteins in an organism of mammals. And, if one of them is broken, there can be various diseases. Most often it has irreversible character as even at the long starvation forced or voluntary to restore all functions happens it is impossible.
The majority of the most important proteins is studied and can be reproduced in vitro. It allows to treat and compensate many diseases successfully. At hormonal insufficiency the replacement therapy is appointed - it is most often hormones of a thyroid gland, hormones of a pancreas and sex hormones. At decrease in immunity the medicinal substances containing protective proteins are appointed.
Today there are amino-acid complexes and for healthy people — athletes, pregnant and other categories. They fill reserves of amino acids that is especially important, when it comes to irreplaceable amino acids and allow an organism not to experience proteinaceous hunger at the moments peak strain. So, serious training by sport during active growth can lead to violation of work of heart for very simple reason - the shortage of proteins for creation of connecting fabric of which not only joints, but also heart valves consist. Protein leaves a usual diet on creation of muscles, connecting fabric begins to suffer. It is only one of examples of importance of healthy nutrition and consequences of its absence for an organism.