Protein-protein interaction affinity chromatography of leukotriene C4 synthase

A novel affinity chromatography purification for human leukotriene C4 synthase is described. It is based on a specific interaction between leukotriene C4 synthase and microsomal glutathione S-transferase which occurs in the presence of magnesium ion. Microsomal glutathione S-transferase was immobilized on NHS-activated Sepharose 4B and used as an affinity matrix. Microsomes from 12-O-tetradecanoyl phorbol 13-acetate-treated human erythroleukemia cells were solubilized with taurocholic acid and applied on the affinity matrix at 0.1 M Mg2+ concentration. After washing with a buffer containing Mg2+, the enzyme was eluted with a glutathione-containing buffer lacking Mg2+. This facile one-step procedure gave a 166-fold purification of leukotriene C4 synthase with a yield of 44%. Analyses of proteins specifically adsorbed to the affinity matrix revealed components with apparent molecular weights of 18, 37, 48, and 60 kDa.