Rarely during the AIDS epidemic has news appeared so promising and hopeful as the testing of drugs that powerfully inhibit the HIV protease enzyme. This article gives an overview of nature of proteases in general, the molecules that inhibit their activity, and a brief account of the development of the HIV protease inhibitors. In contrast, the other, HIV protease, is typical of an important class of enzyme found in varied abundance in all living things, but is unique to HIV in its specificity.
Proteases are proteins that degrade other proteins.
These and many similar enzymes in the gut break down the proteins in food into small fragments that can be easily absorbed into the blood for further metabolism. Individual cells also contain discrete packages of protein-degrading proteases, which they use to destroy and eliminate unwanted substances they take in. Scavenger white blood cells, for example, use these enzymes to break down the bacteria, parasites, and cell debris they engulf, and sperm cells use them to penetrate the outer protein surface of egg cells and achieve fertilization. The coagulation of blood to stop both internal and external bleeding from damaged vessels involves the complex interplay of a series of protease enzymes, and the elimination of these plugs when vessels have healed is brought about by yet another protease. And blood-borne proteases are also key players in the inflammatory response, the body's first line of defense against infection.