Proximal small intestine mucosal surface

Minerals require a suitable mucosal surface across which to enter the body. Resection or diversion of a large portion of small bowel obviously affects mineral absorption. Extensive mucosal damage due to mesenteric infarction or inflamatory bowel disease or major diversion by jejunoileal bypass procedures reduces the available surface area. Minerals whose absorption occurs primarily in the proximal intestine, e.g., copper or iron, are affected differently than those absorbed more distally, e.g., zinc. In addition, the integrity of the epithelium, the uptake of fluids and electrolytes, the intracellular protein synthesis, the energy-dependent pumps, and the hormone receptors must be intact. 

P-D-Fructofuranosidase and leucine p-naphthylamidase are in close proximity on the microvilli membrane of the mucosal cells of rabbit small intestines. It was assumed that where enzymes with, say, A and B antigenicities are in close proximity, the agglutination of vesicles by anti-A antibodies is inhibited by the prior binding of monovalent fragments of anti-B antibodies to enzyme B on the surface. 

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