Why do parietal cells of the gastric mucosa release Chloride anions along the H+-ions, which are pumped into the lumen by the proton-pump. Wouldn't the presence of protons alone be enough to denature proteins?
Mebrane divide basicly enviroment to two disimular sections. This sections differ in lots of chemical/ phycical properties. One of those is electrochemical potential which it can be in the very simple way describe as whole charge of disimular section divided by biomembrane.
So if cell pariental cells pumped into stomach that section will have too much positive value of electrochemical potencial which can repulse pumping more hydrogen ions back to the pariental cell. This lead to freeze hydrogen pumping to the stomach area. Than chloride aniont came to the scene basicly to reduse positive charge and enable to pump tremendous amount of hydrogen to the stomach.