vitamin B12 and intrinsic factor binding take place in which pa of intestine?
Dietary vitamin B12 is normally bound to proteins in food. Pepsin and gastric acid in the stomach degrade these food proteins and release vitamin B12. The free Vitamin B12 then binds to a salivary glycoprotein called haptocorrin (R-binder). In the alkaline pH of the duodenum, pancreatic proteases to degrade the haptocorrin and Vitamin B12 is released again. It then binds tightly to intrinsic factor (IF), a glycoprotein secreted by the parietal cells of the stomach and this binding takes place in the duodenum. The IF-Vitamin B12 complex reaches the terminal ileum and attaches to a receptor on the enterocyte, from where it is absorbed. Vitamin B12 is transpoed in the blood bound to a carrier protein called transcobalamin II and delivered to the peripheral tissues Reference: Harpers illustrated biochemistry 30th edition
Stomach
Duodenum
Ileum
Jejunem
vitamins