Protein - is the most important organic materials, the amount of which prevails over all other macromolecules, which are present in a living cell.They represent more than half the weight of solids both plant and animal organisms.It features a variety of proteins in the cell, some of which are still unknown to science.Yet the main directions of their "work" thoroughly studied.Some needed to stimulate processes in cells and tissues.Other important mineral compounds are transferred through the cell membrane and blood vessels from one organ to another.Some defend the body against foreign pathogens often.One thing is clear - without the protein does not take place no process in our body.
main functions of proteins
functions of proteins in the body are varied.Each group has a specific chemical structure, makes a specialized "work."In some cases, several types of proteins associated with each other.They are responsible for the different stages of the same process.Or affect just a few.For example, the regulatory function of the proteins is carried out by enzymes and hormones.This phenomenon can be represented, for hormone adrenaline remembering.It is produced by the adrenal medulla.Proceeding in the blood vessels, it increases the amount of oxygen in the blood.Raised blood pressure and increased blood sugar.It stimulates the metabolism.Also, the adrenaline is a mediator of the nervous system in fish, amphibians and reptiles.
enzymatic function
Numerous occurring in the cells of living organisms biochemical reactions carried out at high temperatures and pH-neutral.In such conditions, the rate of transmission is too low, so requiring specialized catalysts known enzymes.Their diversity combined in 6 classes that differ in specificity of action.Enzymes are synthesized on ribosomes in cells.Their study involved science enzymology.
Undoubtedly, without enzymes can not function regulatory proteins.They have a high selectivity of action.Their activity can be regulated by activators and inhibitors.In addition, enzymes generally exhibit specificity with respect to substrates.Also enzymatic activity depends on the conditions in the body and in particular in cells.Their flow is influenced by pressure, the acidic pH, temperature, ionic strength of the solution, i.e. the salt concentration in the cytoplasm.
transport function of proteins in cells
should always do the necessary body minerals and organic matter.They are needed as building materials and energy in the cells.But the mechanism is rather complicated they become available.Cellular membranes consist not only of proteins.Biological membranes are based on the principle of a double layer of lipids.Between them the various proteins are embedded.It is important that the hydrophilic portions are located on the surface of the membrane and the hydrophobic - in its thickness.Thus, such a structure makes impermeable shell.Through it can not on their own, without the "aid" to pass such important components, such as sugars, amino acids and ions Metolit.Across the cytoplasmic membrane into the cytoplasm, they are transported specialized proteins, which are mounted in the lipid layers.
transport of substances from one organ to another
But the transport function of the proteins is carried out not only between the intercellular substance and the cell.Some important physiological processes necessary to deliver the substance from one organ to another.For example, a transport protein of blood - serum albumin.He is endowed with the unique ability forms the connection with the fatty acids, which appear in the digestion of fats, with drugs, as well as steroid hormones.Important carrier proteins are, and hemoglobin (delivering oxygen molecules), transferrin (connecting with iron ions) and tseruplazmin (forming complexes with copper).
warning function of proteins
great importance in the course of physiological processes in multicellular organisms are complex receptor proteins.They are mounted in the plasma membrane.They serve to grasp and decoding various kinds of signals which come in a continuous stream of cells not only from adjacent tissues, but also from the external environment.Currently, perhaps the most studied receptor protein is acetylcholine.It is in the range of interneuronal contact on the cell membrane.
But the alarm function of proteins is carried out not only within the cells.Many hormones bind to specific receptors on their surface.Such form the connection and is a signal which activates the physiological processes in cells.An example of such proteins is insulin acting on adenylate cyclase system.
protective function
functions of proteins in the cell are different.Some of them are involved in immune responses.It protects the body from infections.The immune system is able to respond to identified foreign agents synthesis of a vast number of lymphocytes.These substances are capable of selectively damaging these agents, they may be foreign to the organism, such as bacteria, supramolecular particles, or it may be cancer cells.
One of the groups - "beta" lymphocytes - produce proteins that enter the blood stream.They have a very interesting feature.These proteins have to recognize foreign cells and macromolecules.These are then connected with them, forming a complex, which must be destroyed.These proteins called immunoglobulins.Sami alien components - it antigens.A immunoglobulins, which correspond to them - antibodies.
structure function
In the body, in addition to highly specialized, there are also structural proteins.They are needed to provide mechanical strength.These proteins function in the cell is important to maintain the shape and maintaining a young organism.The best known is collagen.This is the main protein of the extracellular matrix of connective tissues.In higher mammals, it is up to 1/4 of the total weight of proteins.Synthesize collagen in fibroblasts, which are the main cells of the connective tissue.
Such functions of proteins in the cell are of great importance.In addition to collagen, known another structural protein - elastin.It is also a component of the extracellular matrix.Elastin is able to grant the ability to stretch the fabric within a certain range, and easily returns to its original shape.Another example of a structural protein - fibroin, which is found in caterpillars silkworms.This is the main component of silk.
motor protein
role of proteins in the cell can not be overemphasized.They take part in the work of the muscles.Muscle contraction is an important physiological process.The result is stored in the form of a conversion of ATP macromolecules into chemical energy.The direct participants of the process are two proteins - actin and myosin.These
motor protein are threadlike molecules that function in contractile system, skeletal muscles.They are also found in non-muscle tissue in eukaryotic cells.Another example of a motor protein - tubulin.From it built microtubules, which are an important element of flagella and cilia.Also microtubule containing tubulin is detected in cells of the nervous tissues of animals.
Antibiotics
is huge protective role of proteins in the cell.Part of it confer on the group, which is called antibiotics.This substance of natural origin, which are synthesized, usually bacteria, microscopic fungi, and other microorganisms.They are aimed at suppressing the physiological processes of other competing organisms.The discovery of antibiotics protein origin were in the 40s.They have revolutionized medicine, giving it a powerful impetus to the development.
By their chemical nature, antibiotics - a very diverse group.They differ in the mechanism of action.Some inhibit protein synthesis within the cell, the second block the production of important enzymes, inhibit the growth of third, fourth - propagation.For example, well known streptomycin interact with ribosomes of the bacterial cells.Thus, they dramatically slows protein synthesis.The data does not antibiotics interact with eukaryotic ribosomes human body.This means that for the higher mammals, these substances are non-toxic.
This is not all of the functions of proteins in the cell.Table antibiotic substances and to determine other highly specialized actions that these specific natural compounds are able to exert on the bacteria and not only.It is currently under study antibiotic protein origin, which in interaction with DNA violate the processes associated with the implementation of hereditary information.But while these materials are used only for chemotherapy of oncological diseases.An example of such an antibiotic substance is dactinomycin synthesized actinomycetes.
Toxins
proteins in cells function as highly specific and even eccentricity.A number of live organisms produced poisons - toxins.By their nature, are proteins and complex low molecular weight organic compound.As an example, a poisonous fungus flesh is pale toadstool.
Spare and food proteins
Some proteins act as food embryos of animals and plants.There are many examples.The value of the protein in the cell cereal seeds enclosed in it.They will nourish the germ of emerging plants in the early stages of its development.In animal food proteins are egg albumin and milk casein.
unexplored properties of proteins
examples above - only the part that has already been studied enough.But in nature there is a lot of mysteries.The proteins in the cells of many species are unique, and now even to classify them difficult.For example, monellin - protein found and isolated from African plants.It tastes sweet, but it does not cause obesity and non-toxic.In the future, it can be an excellent substitute sugar.Another example - a protein found in some Arctic fish, it prevents freezing blood, acting as antifreeze in the literal sense of the comparison.A number of insect wings in the compounds identified protein resilin with a unique, almost perfect elasticity.And that's not all examples of substances that are only to be examined and classified.
