title: Biochemical studies on a 12-lipoxygenase in human uterine cervix.
abstract: Human uterine cervix possesses a high 12-lipoxygenase activity; this enzyme has been isolated in a purified form from the squamous epithelial region of human cervix and its major properties have been investigated. Enzyme activity was present in all subcellular fractions obtained by centrifugation; the highest specific activity was associated with the microsome fraction (160,000 X g pellet). Purification of the enzyme was achieved by acetone precipitation, ion exchange chromatography on CM-cellulose and affinity chromatography on linoleyl-aminoethyl-Sepharose. The product from the incubation of sodium [1-14C]arachidonate with crude enzyme extracts co-chromatographed with authentic 12-hydroxyeicosatetraenoic acid, but the purified enzyme gave a product that behaved like the 12-hydroperoxy derivative. The enzyme had optimum activity at pH 6.5, a Km of 15 microM for arachidonic acid and was stimulated by ATP and Ca2+. Enzyme activity was inhibited by esculetin, nordihydroguaiaretic acid, eicosatetraynoic acid, detergents at concentrations greater than 0.1% (w/v) and preincubation of substrate with GSH and GSH peroxidase. The occurrence of a high 12-lipoxygenase activity is discussed in relation to the specific physiological functions of this tissue.
mesh_terms: D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D000328:Adult; D001091:Arachidonate Lipoxygenases; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism; D002584:Cervix Uteri / Q000201:enzymology*; D002845:Chromatography; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D005260:Female; D005978:Glutathione / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006893:Hydroxyeicosatetraenoic Acids / Q000378:metabolism; D008084:Lipoxygenase / Q000302:isolation & purification / Q000378:metabolism*; D016859:Lipoxygenase Inhibitors; D008861:Microsomes / Q000201:enzymology; D008875:Middle Aged; D013347:Subcellular Fractions / Q000201:enzymology
chemical_list: D001095:Arachidonic Acids; D006893:Hydroxyeicosatetraenoic Acids; D016859:Lipoxygenase Inhibitors; D016718:Arachidonic Acid; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D001091:Arachidonate Lipoxygenases; D008084:Lipoxygenase; D005978:Glutathione