Beiträge zur Chemie des Insulins. XII. Mitteilung über krystallisiertes Insulin.

Abstract

Difficulties were encountered in crystallizing insulin from pig''s pancreas by Abel''s method. The material obtained, which was probably not uniform, had a lower S content than crystalline insulin prepared from ox pancreas. Insulin which had been coagulated with N/10 HC1 for 1 hr. at 100[degree] C. could not be obtained again in crystalline form. The degree of inactivation of insulin by acetylation varies with the conditions employed and is probably due to the blocking of free amino groups. The treatment of insulin with benzaldehyde gives an inactive product which cannot be reactivated. The action of dilute alkali on insulin was studied and it was concluded that a relationship existed between the degree of inactivation and the ammonia liberated.