GLYCOLIPIDS

From Big Medical Encyclopedia

GLYCOLIPIDS (glycosphingolipids) — the lipids containing sugar in structure of a molecule; play an essential role in functioning of biological membranes.

Glycolipids in an organism of animals were discovered by L. W. Thudichum in the second half of 19 century, however interest in them increased almost in 100 years after their opening. Contain preferential in tissue of a brain, in much smaller quantity they are found also in other animal fabrics.

Three basic groups of G. are known: cerebrosides (see), sulfatides (see) and gangliosides (see). The simplest G. on a chemical structure are cerebrosides; they consist from sphingosine (see), the rest fat to - you and hexoses (see). The structure of cerebroside can be presented by the following scheme:

Sulfatides differ from cerebrosides in existence in a molecule a chamois to - you; in other words, the sulfatide represents tserebrozidsulfat, in Krom sulfate is etherified on the third carbon atom of hexose. In a brain of mammals sulfatides as well as cerebrosides, are preferential in white matter, but contents is much lower than them, than the content of cerebrosides.

Gangliosides are the most difficult constructed by G. In addition to the components characteristic of cerebrosides, gangliosides contain still sialic acids (see), most often N-atsetilneyraminovuyu to - that.

Unlike cerebrosides and sulfatides, gangliosides are preferential in gray matter of a brain and are concentrated in plasma membranes of nervous and glial cells. Especially there are a lot of gangliosides in synaptic membranes.

Biol, G.'s role finally is not found out. All of them are structural components biol, membranes, and it is natural to connect their role with function of these membranes. Attribute to cerebrosides a special role in immunol, reactions; they are the most immunoactive connections of a brain. Function of sulfatides is connected, apparently, with active transport of sodium, and gangliosides consider as an important component in the course of transfer of nervous impulse. Thus, it is difficult to speak about any specific function of each of G. Veroyatno, all of them are more or less multifunctional.

The serious inborn illness connected with disturbance of exchange of G., hl is known. obr. with their accumulation in a brain and other fabrics. At gangliozidoza, napr, diseases Teja — the Saxophone (see. Amaurotic idiocy ), the maintenance of gangliosides in tissue of a brain sharply increases. At Krabbe's disease (see. Leukodystrophy ) in a brain, and at a disease to Gosha (see. to Gosha disease ) in a liver and a spleen excess amounts of cerebrosides collect, and at a metachromatic leukodystrophy — sulfatides.

See also Membranes biological .


Bibliography: Zhukova I. G. and Smirnov G. P. Glycolipids, Usp. biol, chemical, Under the editorship of V. L. Kretovich, etc., t. 9, page 220, M., 1968, bibliogr.; To p e p with E. M. Glycolipids of a brain and their functional value, in book: Usp. neurochemical, under the editorship of E. M. Krepsa, page 50, L., 1974, bibliogr.; H about 1 m M. Metabolism and function of gan-gliosides, Goteborg, 1972.

V. I. Rozengart.

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