enzyme target

An enzyme is a biological catalyst — a tiny molecular machine that speeds up a specific chemical reaction in the body. An enzyme target is one such machine that a drug deliberately interferes with, usually by slowing or stopping it, to produce a therapeutic effect. If a receptor is a lock, an enzyme target is more like a production line that a drug can jam.

Most enzyme-targeting drugs are inhibitors. They may compete with the enzyme's natural substrate for the active site, bind elsewhere to distort the enzyme's shape, or in some cases attach permanently and disable it. By blocking the enzyme, the drug lowers the amount of the enzyme's product or lets its substrate accumulate, depending on which matters for the disease.

Enzymes are second only to receptors as drug targets and underlie many blockbuster medicines: statins inhibit HMG-CoA reductase, ACE inhibitors block angiotensin-converting enzyme, and aspirin inactivates cyclo-oxygenase. A practical caveat is that the same enzyme may serve several roles in the body, so inhibiting it can produce both the intended benefit and unwanted effects elsewhere.