Aluminum binding activity in canine duodenal mucosal extracts

Aluminum binding activity in soluble mucosal extracts from canine duodenum could be demonstrated in a single peak corresponding to proteins in the molecular weight range of 9,000 to 10,000 daltons following chromatography on Sephadex G100. Peak calcium binding activity was observed in these same fractions. These results suggest that there exist soluble proteins in duodenal mucosa which have affinity for both aluminum and calcium and that the absorption of aluminum through the gastrointestinal tract may be promoted by these proteins possibly in competition with calcium.