Which enzyme requires a highly acidic environment to function?

Pepsin is the enzyme that requires a highly acidic environment to function effectively. It is produced in the stomach and is essential for the digestion of proteins. The stomach's gastric juices contain hydrochloric acid, creating an acidic pH that activates pepsinogen (the inactive form of pepsin) into its active form, pepsin. This activation is crucial because pepsin works optimally in an acidic environment, breaking down complex protein molecules into smaller peptides for further digestion.

In contrast, amylase, lactase, and trypsin function in different environments. Amylase works primarily in a neutral to slightly alkaline pH found in the mouth and small intestine, where it breaks down starches into sugars. Lactase also operates in the small intestine where lactose is digested into glucose and galactose, requiring a neutral pH for optimal activity. Trypsin, on the other hand, is activated in the small intestine and works best in a more alkaline environment, following the acidic conditions in the stomach.