Protein-coding gene in the species Homo sapiens
Haptocorrin (HC) also known as transcobalamin-1 (TC-1) or cobalophilin is a transcobalamin protein that in humans is encoded by the TCN1 gene.[3] One essential function of haptocorrin is protection of the acid-sensitive vitamin B12 while it moves through the stomach. A second function is serum HC binding of the great majority of circulating vitamin B12, rendering it unavailable for take-up by cells. This is conjectured to be a circulating storage function.