Localization of Arachidonate 12‐Lipoxygenase in Canine Brain Tissues

Abstract

Abstract: The cytosol fraction from a thoroughly imgated canine cerebrum was subjected to immunoaffinity chromatography using a monoclonal antibody against porcine leukocyte 12‐lipoxygenase. Arachidonate 12‐lipoxygenase eluted from the column with some retardation. The enzyme, with a specific activity of 9 nmol/min/mg of protein, converted arachidonic acid to 12( S )‐hydroperoxy‐5,8,10,14‐eicosatet‐raenoic acid. The enzyme was active not only with arachidonic acid, but also with linoleic and α‐linolenic acids. In contrast, 12‐lipoxygenase of canine platelets was almost inactive with linoleic and α‐linolenic acids, and the platelet enzyme was also distinguished from the cerebral enzyme in terms of reactivity with the anti‐12‐lipoxygenase antibody. 12‐Lipoxygenase activity was also detected in the cytosol fractions of other parts of canine brain: basal ganglia, hippocampus, cerebellum, olfactory bulb, and medulla oblongata.