title: [Non-antioxidative mechanism of cytochrome P-450 stabilization by alpha-tocopherol: the effectiveness in avitaminosis E].
abstract: The efficiency of alpha-tocopherol as a 7-etoxycumarine deethylase protector in rat liver microsomes damaged by phospholipase A2 at various levels of vitamin E was studied. No selective damage of cytochrome P-450 isoforms possessing a catalytic activity towards 7-etoxycumarine under vitamin E deficiency was observed. Phospholipase A2 decreased the deethylase activity of cytochrome P-450, the efficiency of the damaging action being dependent on vitamin E content in the liver. Exogenous alpha-tocopherol exerts an antiphospholipase effect and protects 7-etoxycumarine deethylase; the protective action is inversely proportional to vitamin E level in the liver. Under normal conditions the damaging effect of phospholipase A2 on cytochrome P-450 is mainly provided for by lysophospholipids, while under vitamin E deficiency both lysophospholipids and free fatty acids exert a damaging action. A possible mechanism of the stabilizing effect of alpha-tocopherol may consist in the interaction of the chromanol nucleus in the vitamin E molecyule both with lysophospholipids and with free fatty acids.
mesh_terms: D015660:7-Alkoxycoumarin O-Dealkylase; D000818:Animals; D003374:Coumarins / Q000378:metabolism; D065607:Cytochrome P-450 Enzyme Inhibitors; D006868:Hydrolysis; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology / Q000378:metabolism; D010105:Oxygenases / Q000037:antagonists & inhibitors; D010741:Phospholipases A / Q000378:metabolism; D054467:Phospholipases A2; D010743:Phospholipids / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D014810:Vitamin E / Q000378:metabolism / Q000494:pharmacology*; D014811:Vitamin E Deficiency / Q000201:enzymology / Q000378:metabolism*
chemical_list: D003374:Coumarins; D065607:Cytochrome P-450 Enzyme Inhibitors; D010743:Phospholipids; D014810:Vitamin E; C017299:7-ethoxycoumarin; D010105:Oxygenases; D015660:7-Alkoxycoumarin O-Dealkylase; D010741:Phospholipases A; D054467:Phospholipases A2
vernacular_title: Neantioksidantnyĭ mekhanizm stabilizatsii tsitokhroma P-450 alpha-tokoferolom: éffektivnost' pri avitaminoze E.