Isolation and some properties of dioxygenase and co-oxidase activities of adult human liver cytosolic lipoxygenase.

摘要: The evidence presented here constitutes the first report on occurrence of lipoxygenase (LO) activity in adult human liver. LO was isolated free hemoglobin from whole liver cytosol by affinity chromatography using a concanavalin-A sepharose 4B column, and some properties its dioxygenase co-oxidase activities were examined. High-pressure liquid (HPLC) analyses arachidonic acid metabolites suggested presence 5-, 12-, 15-LO Linoleic converted into 13-hydroperoxyoctadecadienoic acid. with Vmax value 1.74 mumoles/min/mg protein Km 0.48 mM noted different concentrations linoleic at pH 10. markedly stimulated calcium, ATP, hydrogen peroxide, KCl assay medium. Under optimum conditions, all xenobiotics tested cooxidized enzyme preparations Kinetic data obtained for benzidine oxidation yielded 0.53 90.9 nmoles/min/mg protein. At present, significance these findings vivo toxicity is unknown. acid-dependent thermolabile inhibited micromolar several classical inhibitors, further confirming involvement reactions.