Answer to Question #163158 in Economics for Philip

Question

Classify protein and give four food example each.

Answer 1

According to the chemical structure of molecules, all proteins are divided into simple and complex.

Simple proteins (proteins) are composed only of amino acids.

Complex proteins (proteids) are composed of globular proteins and a non-protein component. The non-protein portion of a complex protein is called the prosthetic group.

The prosthetic group can be represented by compounds of various chemical nature. Complex proteins are subdivided depending on their structure and properties:

chromoproteins - contain a colored component (hemoglobin, myoglobin, cytochromes, chlorophyll) as a non-protein part;

glycoproteins - contain carbohydrates;

nucleoproteins - contain nucleic acids;

lipoproteins - contain lipids;

phosphoproteins - contain a phosphoric acid residue;

metalloproteins - contain a complex bound metal.

Simple proteins

Simple proteins include albumin, globulins, protamines, histones, prolamins, glutelins, and proteinoids.

Albumin and globulins are proteins that are found in all tissues. Blood serum is the richest in these proteins. Albumin accounts for more than half of blood plasma proteins.

Albumin

Albumin - make up the bulk of animal and plant proteins. Albumin is a globular protein.

Albumin - proteins of a relatively small molecular weight 25000-70000, have a pronounced acidic character, since they contain a large amount of aspartic and glutamic acids.

They dissolve in pure water and dilute solutions of acids, alkalis and salts. Albumin is precipitated from aqueous solutions with ammonium sulfate only when the solution is completely saturated, because these are highly hydrated proteins.

When boiled, they curl up and precipitate in the form of thick flakes of denatured protein. The formation of foam on milk, the thickening of the contents of the eggs during cooking is explained by the denaturation of the albumin. The foam formed during cooking fruits and vegetables is partly composed of coagulated plant albumin.

Albumin - proteins of predominantly animal origin. These include blood serum albumin, milk lactalbumin, egg white ovalbumin, animal muscle myoalbumin, as well as wheat, rye and barley leukemia, buckwheat and soy legumenin, and castor bean ricin.

Albumin performs nutritional, transport, and detoxifying functions in the body.

A characteristic property of albumin is its high adsorption capacity. They adsorb polar and non-polar molecules, performing a transport role.

They transport hormones, cholesterol, bilirubin, drugs, and calcium ions.

Albumin binds toxic compounds - alkaloids, heavy metals, bilirubin.

Due to their high hydrophilicity, small molecular size, and significant concentration, albumin plays an important role in maintaining the osmotic pressure of the blood. Albumin provides 80% of the osmotic pressure of the blood compared to all other serum proteins.

Albumin is synthesized primarily in the liver and is rapidly renewed.

Globulins

Globulins are a widespread group of globular proteins that usually accompany albumin. Globulins have a higher molecular weight than albumin. Globulins are weakly acidic or neutral proteins.

Globulins are soluble in weak saline solutions, insoluble in distilled water, and precipitate at 50% or more saturation of solutions with ammonium sulfate, coagulate when heated.

Globulins include serum, milk, egg, muscle, and other globulins.

There are many globulins in food. Peas contain the protein legumin, soy contains glycinin, bean seeds contain phaseolin, potatoes contain tuberin, blood contains fibrinogen, milk contains lactoglobulin, eggs contain egg globulin, and hemp contains edestin.

Globulins in the body perform nutritional, protective, transport functions.

In the blood, globulins transport cholesterol, phospholipids, triglycerides, iron ions (Fe2 +), copper (Cu2 +), vitamin B12. In milk, lactoglobulins and lactalbumins also perform a transport function.

Globulins are produced by the liver and the immune system.

Protamine

Protamines are low molecular weight positively charged nuclear proteins with pronounced basic properties (alkaline proteins), with a low molecular weight of 4000–12000, and contain 60–85% arginine.

Protamines are an integral part of many important complex proteins (nucleoproteins) that make up the cell nuclei. In the nuclei of cells, they are in a complex with DNA.

Protamines are readily soluble in water, acidic and neutral media, and precipitate in alkaline media, not precipitated by boiling.

Protamines are found in sperm nuclei in fish. They constitute the fraction of the main protein in mature fish sperm.

Protamines are found in the semen of some fish species.

They perform mainly a structural function, therefore they are present in cells that are not capable of dividing.