which substance regulates the ph of the stomach
The stomach contains hydrochloric acid, which has a pH of generally 1-3.   These optimal pH levels must be present in order for pepsin (a protein-digesting enzyme) to functâ¦ion. If the pH is not acidic, pepsin will only be present in its inactive form, pepsinogen, and protein digestion will effectively occur.   Uhh.. hope that's what you were looking for. The second part is just a bit more detail as to why the pH of stomach is important.