Translations:Vitamin B12/69/en

After the IF/B₁₂ complex binds to cubam the complex is disassociated and the free vitamin is transported into the portal circulation. The vitamin is then transferred to TC2, which serves as the circulating plasma transporter, Hereditary defects in production of TC2 and its receptor may produce functional deficiencies in B₁₂ and infantile megaloblastic anemia, and abnormal B₁₂ related biochemistry, even in some cases with normal blood B₁₂ levels. For the vitamin to serve inside cells, the TC2-B₁₂ complex must bind to a cell receptor protein and be endocytosed. TC2 is degraded within a lysosome, and free B₁₂ is released into the cytoplasm, where it is transformed into the bioactive coenzyme by cellular enzymes.