Competition Between Apo and Holo Transcobalamin II (TC II) For the TC II-Mediated Uptake Process 1

Summary

The uptake process of transco-balamin II-cobalamin (TC II-Cbl) of HeLa cells and RPMI 6410 lymphocytes was evaluated for its capacity to respond to apo TC II, that not carrying Cbl. At 4° there was partial competition by apo TC II for holo TC II in the primary phase of uptake. However, at 37° for 3 hr there was only slight competition for the process by which TC II-Cbl penetrates the cell.