Complex sentence: Inside the cells, B 12 dissociates once again and binds to another protein, transcobalamin II (TCN2); the new complex can then exit the epithelial cells to be carried to the liver.
Split into simpler sentences: Inside the cells, B 12 dissociates once again and binds to another protein, transcobalamin II (TCN2). The new complex can then exit the epithelial cells to be carried to the liver.