Gelation of casein and soybean globulins by transglutaminase.

Guinea pig liver transglutaminase is a Ca2 + dependent enzyme which catalyzes the formation of inter-and intramolecular £-(/y-glutamyl)lysyl cross-links between protein molecules.Wehave found that solutions of several proteins (asl-casein, and soybean US and 7S globulins) were gelatinized firmly by transglutaminase.The gel formation depended on the protein concentration.In the case of asl-casein, a reaction mixture containing below 2%was incapable of gelation.However, above 3%, a firm gel was formed by transglutaminase.As to soybean USand 7S globulins, reaction mixtures containing below 5%did not form gels, while, above 8%, firm gels were formed.The protein solutions in the presence of EDTA, an inhibitor of transglutaminase, were not gelatinized on treatment with transglutaminase.Thus, transglutaminase and a higher con-