The basis of blood plasma are proteins contained in the range from 60 to 80 g/l, which is approximately four percent of all proteins in the body. There are about a hundred different proteins in human blood plasma. According to their mobility, they are divided into albumins and globulins. Initially, this division was based on the solubility method: albumins dissolve in a pure liquid, and globulins only in the presence of nitrates.
Plasma proteins
Among proteins, there is more albumin in the blood - about 45 g/l. It plays a huge role in maintaining blood pressure KO, and also serves as a reservoir for the reserve of amino acids.
Albumins and globulins have different abilities. The first type of proteins can bind lipophilic substances. Thus, conglomerates have the opportunity to work as carrier proteins for long-chain fatty acids, various medicines, bilirubin, vitamins, and steroid hormones. Also albuminable to bind magnesium and calcium ions.
Albumin and globulin proteins act as transport for thyroxine, its metabolite iodothyronine.
Destruction and formation of proteins
Most plasma proteins are formed in the liver, with the exception of immunoglobulins (produced by cells of the immune system) and peptides (produced by the endocrine system).
Albumins and globulins are different in structure. All proteins, except albumin, belong to glycoproteins, contain oligosaccharides and are attached to amino acid residues. Acetylneuraminic acid often acts as a terminal residue. If it is cleaved off by neuraminidase, terminal residues of galactose appear on the surface of the protein. Remains of desialized proteins are recognized, begin to change galactoses on hepatocytes. In the liver, these already obsolete proteins are removed by endocytosis. In this way, saccharides on the surface set the lifetime of plasma proteins, and also determine the elimination half-life, which can be up to several weeks.
In a he althy body, the concentration of albumin and globulins in the blood is maintained at a constant level. But there are situations when indicators change. This occurs in diseases of the organs involved in the synthesis and catabolism of proteins. Damage to cells through cytokines increases the formation of albumin proteins, globulins, fibrinogens and some others.
Electrophoresis
Proteins and other charged macromolecules can be separated by electrophoresis. Among all existing methodsdivision, it is especially important to highlight electrophoresis on a carrier, namely, on a cellulose acetate film. In this case, whey proteins move towards the anode, being divided into several fractions. After division, the proteins are stained with a dye, which makes it possible to estimate the amount of protein in the stained bands.
Protein Ratio
When analyzing the amount of protein in blood plasma, not only the level of albumin and globulin is determined, but also the ratio of these substances to each other is determined. Normally, there should be a ratio of 2: 1. If they deviate from these indicators, they speak of pathology.
A decrease in the ratio of albumin to globulin may indicate the following:
- decrease in albumin synthesis - liver cirrhosis;
- low albumin levels can be observed in kidney pathologies.
An increase in the ratio of albumin to globulin may indicate such pathologies:
- hypothyroidism;
- leukemia;
- new growths;
- impaired growth hormone production.
With a decrease in globulin, autoimmune diseases, myeloma are also detected in some cases.
Albumins help maintain osmotic pressure in the body. The test for total protein allows you to evaluate how the disease proceeds, monitor oncology, detect violations of the kidneys and liver, determine the cause of edema, and also evaluate the quality of nutrition.
