Abstract
Arachidonate 5-lipoxygenase initiates the biosynthesis of leukotrienes which are known as mediators of inflammation and anaphylaxis. The enzyme was highly purified from the cytosol fraction of porcine leukocytes by immunoaffinity chromatography using a monoclonal antibody raised against a crude enzyme preparation .The purified enzyme showed the leukotriene A synthase activity (5-hydroperoxy acid → 5-hydroperoxy acid). Several lines of enzymological finding confirmed that both activities were attributed to the same enzyme protein .The enzyme also oxygenated the 6-position of 5-hydroperoxy acid, and catalyzed the lipoxin formation. Immunohistochemical study with anti-5-lipoxygenase antibody showed the localization of the enzyme in the cytosol of porcine neutrophils, eosinophils and mast cells but not in lymphocytes. Furthermore, bronchiolar epithelial cells and pancreatic acinar cells were positively stained.
