EFIROGLYUKURONOVY ACIDS

From Big Medical Encyclopedia

EFIROGLYUKURONOVY ACIDS — substitution products of hydrogen atoms of hydroxylic group in a molecule of glucuronic acid on a hydrocarbon radical with the general formula:



where R is the hydrocarbon radical.

Education E. to. in a liver at the person and at animals is one of the most important mechanisms of a detoxication as poisonous alien, including and medicinal, substances (xenobiotics), and nek-ry natural matabo the litas capable to become for an organism endogenous poisons. Thus (Z-B-glyukuro-novaya to - that (see. Hexuronic acids, At fatal acids) along with sulphuric acid (see), glycine (see), taurine (see), cysteine (see), etc. is a peculiar internal antidote of an organism. In a liver (see) by formation of efiroglyukuronovy acids, i.e. formations of so-called conjugates with glucuronic to - that, are neutralized putrilages of proteic matters in intestines (see Rotting), phenols (see), cresols (see), skatole (see), an indole (see); skatole and an indole are oxidized previously in ska toxyl and indoxyl. Steroids (see), thyroxine (see), etc. belong to the metabolites forming efiroglyuku-ronovy acids in a liver bilirubin (see).

Biosynthesis E. to. it is localized in a smooth cytoplasmic reticulum of hepatocytes. For formation of radio communication (see Ethers) glucuronic to - that shall turn previously into the active fosforilirovanny form — Uri-dindifosfatglyukuronovuyu to - that (Udfglyukuronat) as a result of transferazny reaction about uridine-triphosphate (see Phosphorylation).

Process of formation of efiroglyukuronovy acids in a human body and animals is catalyzed hepatic Udfglyukuronozil-transferazoy (KF 2.4.1.17) which genetically caused insufficiency is one of the reasons of development of a hemolitic disease of newborns (see). Activity Udfglyukuronoziltransfe-razy in a liver at children below, than at adults therefore the detoxication of medicinal substances and their derivatives in a children's organism is more limited that needs to be considered during the definition of a dose of drug. Fiziol. jaundice of newborns is caused by the same reason. Disturbance of education E. to. in a liver owing to patol. proni-


tsayemost of cellular membranes or metabolism of hepatocytes leads changes to poisoning of an organism with toxicants, it is the cornerstone of enzymopathic jaundice at Gilbert's syndromes — Meylengrakhta and Krigler — Nayara (see Hepatoses) and other morbid conditions.

However education E. to. not always it is directed only to neutralization of substances, toxic for an organism. Thanks to conjugation with glucuronic to - that originally fat-soluble (hydrophobic) substances become water-soluble (hydrophilic), an opportunity for their transport, metabolism and removal with bile (see) or urine thereby is created (see).

Methods of definition E. to. — see Uronic acids.

See also Glucuronides.

Bibliography: Berezov T. T. and To

rovkin B. F. Biological chemistry, page 588, M., 1982; To r yu Zh. Biokhimiya, the lane with fr., page 422, M., 1979;

Park D. B. Biochemistry of alien connections, the lane with English, page 93, M., 1973;

Hashen R. and Sheikh D. Sketches on pathological biochemistry, the lane with it., page 165, M., 1981. N. G. Budkovskaya.

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