Human digestive system in the small intestine. Water and minerals are reabsorbed back into the blood in the colon of the large intestine, where the environment is slightly acidic. Some vitamins, such as biotin and vitamin K produced by bacteria in the gut flora of the colon are also absorbed. The parietal cells in the fundus of the stomach, produce a glycoprotein called intrinsic factor which is essential for the absorption of vitamin B12. Vitamin B12 (cobalamin), is carried to, and through the stomach, bound to a glycoprotein secreted by the salivary glands - transcobalamin I also called haptocorrin, which protects the acid-sensitive
Calponin 3, acidic Calponin 3, acidic Calponin 3. acidic is a protein that in humans is encoded by the "CNN3" gene. The "CNN3" gene is located at 1p22-p21 in the human chromosomal genome. "CNN3" gene contains 7 exons and encodes calponin 3, a 36.4-kDa protein consisting of 329 amino acids with isoelectric point (pI) of 5.84. Calponin 3 is known as acidic calponin. Among three isoforms of calponin, less is known for the gene regulation and function of calponin 3. Nonetheless, much has been learned from extensive studies on the homologous genes "CNN1" and "CNN2" that encode calponin 1 and calponin 2. "CNN3"