Studies on the intestinal disaccharidases of the pigeon IV. - immunochemical properties of sucrase«isomaltase and maltase·glucoamylase

Antisera against purified pigeon small intestinal sucrase-isomaltase (S-I) and maltase-glucoamylase (M-G) were prepared from rabbits. Both sera showed cross-reactivity. It was demonstrated that the sucrase-isomaltase was purified to homogeneity, supporting our earlier results of SDS-PAGE of pigeon intestinal disaccharidases. Both the sucrase·isomaltase and maltase-glucoamylase activities were not inhibited by either specific or cross-reacting antibodies even when a several fold of either antibody was present. It is inferred from these immunochemical results that the two complexes in the pigeon intestine share many structural identities, and that their catalytic site(s) may not be involved in their antigenic domains.