SPHINGOMYELINS

From Big Medical Encyclopedia

SPHINGOMYELINS — difficult lipids, amino alcohol sphingosine or its polyunsaturated analogs, sincaline, the rest of phosphoric acid and the rest of fatty acid is a part to-rykh. Genetically caused disturbance of exchange of S. is the cornerstone of heavy enzymopathies (see).

L. J. W. Thudichum were open for page in 1884 and are allocated to them in 1901. They are eurysynusic in the nature, are a part of membranes of animal and plant cells. S. nervous tissue is especially rich. Apprx. 20% of all phospholipids of a brain (see. Phosphatides ) falls to S. V share a myelin, white and gray matter of a brain of the person S. make 7 — 8% of total quantity lipids (see). In phospholipids of membranes of erythrocytes 15 — 16% of S. are revealed, and 80 — 85% of these S. are in a periblast of membranes. S.'s concentration is equal in a blood plasma of the person to 10 — 50 mg / 100 to ml (according to other data, 10 — 30 mg / 100 to ml) that averages 18 — 20% of total quantity of phospholipids of a blood plasma. Pages are a part lipoproteids (see) a blood plasma.

the Constitutional formula of the sphingomyelin containing palmitoleic acid.

Pages belong to to sphingolipids (see) since contain sphingosine (see. Sphingosines ), and to phospholipids since contain the rest phosphoric to - you (see. Phosphoric acids ). Most often are S.'s part fatty acids (see) with the chain constructed of 24 S-atoms (lignoceric, cerebronic, nervonovy to - you), however can be S.'s part also fat to - you, the containing 22, 20 and 18 S-atoms, napr, palmitoleic to - that (fig.). Page of a rastvorima in chloroform, methanol and their mix, t ° pl 196 — 198 °. Unlike other phospholipids C. are steady against alkaline hydrolysis, and at acid hydrolysis break up to components.

Sphingosine participates in S.'s synthesis. After accession to with fingozin at the rest fat to - you in reaction with atsil-KOA under action sphingosine-acyltransferase (KF 2.3.1.24) is formed ceramide (N-atsilsfin-gozin), to-ry, reacting about cytidinediphosphate (TsDF) - sincaline, catalyzed by ceramide-sincaline-phosphotransferase (KF 2. 7. 8. 3), S. Tseramid-holin-fosfo-transferaza forms it is found in a liver, a brain and a spleen of the person and animals. There is another, obviously rare, the way of biosynthesis of S., according to the Crimea sphingosine reacts with TsDF-sincaline in the beginning, and formed sfingozinfosfo-rilkholin reacts with KOA-derivatives fat to - you,

S. V leading to education a spleen, a liver, kidneys, a brain and multiple forms are found in other human organs (see. Isoenzymes ) sphingomyelinases (sphingomyelin-phosphodiesterase, KF 3. 1. 4. 12) — the enzyme which is specifically hydrolyzing S. with formation of ceramide and a fosforilkho-lin. At Nimann's disease — Peak (see. Nimanna — Peak a disease ) at adults observe S.'s accumulation hl. obr. in a spleen, a liver and a brain (see Tezaurismoza). At children at this disease note mental retardation; disturbance of exchange of S. eventually conducts by early death. Forms of a disease of Nimann — Peak (infantile, or juvenile) are caused by insufficiency of any isoenzyme of a sphingomyelinase.

S.'s definition in biol. objects consists in receiving the relevant fraction of phospholipids after division of their mix by means of a chromatography (see) on paper or in a thin coat of silica gel. S.'s definition in blood serum on Robinsa in L. Svennerholm's modification is based that S. represent not saponifiable fraction of phospholipids. During the heating in the beginning with caustic heat, and then with salt to - that phosphorus C. passes into fat-soluble fraction, and phosphorus of other phospholipids — in water-soluble. S.'s definition, thus, comes down to determination of amount of fat-soluble phosphorus. Normal in blood serum S.'s maintenance established by this method makes apprx. 49 mg! 100 ml.



Bibliography: See bibliogr. to St. Sphingolipids .


N. V. Gulyaeva.

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