It took two years to get a stable, crystalline form of the hepatitis C protease enzyme for study.

FORBES: Magazine Article

Thus far the most promising new class of such enzyme-attacking drugs looks to be protease inhibitors, best known for combating the progress of HIV infections in the body.

FORBES: Magazine Article

These work by binding chemically to that enzyme's active site to inhibit its action. (Protease cuts the raw chain of virus protein produced by a subverted cell into functional molecules.) However, the mechanism is not quite identical.

ECONOMIST: Nanotechnology in biology

The hepatitis C protease is a particularly tough target because, unlike the similar enzyme in HIV, it has relatively few nooks and crevices into which to cram a druglike chemical.

FORBES: Magazine Article