Cobalamin binding intrinsic factor is a glycoprotein produced by the parietal cells of the stomach. Its main function is to bind to vitamin B?? （cobalamin） in the digestive tract. This binding protects cobalamin from degradation and facilitates its absorption in the ileum of the small intestine. The complex of intrinsic factor and cobalamin is recognized by specific receptors on the ileal epithelial cells, allowing for the efficient uptake of vitamin B?? into the bloodstream. Deficiency of intrinsic factor can lead to pernicious anemia, as it impairs the body's ability to absorb vitamin B??, which is essential for normal hematopoiesis and neurological function.