STUDIES ON ISOLATION AND PURIFICATION OF GLUCAGON

Methods of glucagon purification from the insulin process was studied. The salt precipitate of insulin was used as starting material which was passed over a macroproporous strong acid ion-exchange resin column. Insulin was not adsorbed and flew out in the effluent (A). It was then eluted with dilute NH₄OH solution and the protein solution containg glucagon (B) was obtained. After separation of solution (B) by gel filtration, the fraction (C) was a glucagon-rich fraction. Concentrated (C) was separated by DEAE-cellulose chromatography column. Pattern of disc electrophoresis of fraction (D) appeared to be homogeneous. The electrophoresis behavior of (D) was essentially identical to standard sample and the increase of blood suger in rabbits showed a retention of whole activity. Crystallization of concentrated (D) was performed at pH 8.5. The crystals obtained were rhombedodecahedrons in shape. Insulin was also obtained from solution (A) in crystalline form. All samples obtained from ion-exchange chromatography, gel filtration and DEAE-cellulose chromatography as described above were concentrated and desalted by using a new type organic absorbent. The yield of glucagon was 1 mg per kg of porcine pancreas. The present method will afford a way or new method of isolating both glucagon and insulin from insulin process.