Which of the following enzymes acts efficiently at pH 2?
Most enzymes act under pHs between 6 and 8, a range that corresponds to the general acidic level of cells and blood. There are enzymes, however, that act only under very acid or very alkaline pH. Therefore, enzyme activity depends on pH range.
In the stomach, for example, gastric juice has a very low pH, around 2. Nonetheless, the enzyme pepsin acts to intensively digest proteins. In the duodenum, pancreatic secretions increase the pH of the intestinal juice to allow other digestive enzymes, such as trypsin, to act.