Before revision: KDEL receptor binding is dependent on pH, in which the ligand (target protein) binds strongly to the receptor in the cis-Golgi due to the unique low pH (6, is strongest binding) characteristic of the biochemical environment of the cis-Golgi network.
After revision: KDEL receptor binding in in vitro experiments pH 5 showes dependent on pH, in which the ligand (target protein) binds strongly to the receptor in the cis-Golgi due to the unique low pH (6, is strongest binding) characteristic of the biochemical environment of the cis-Golgi network.