Protease inhibitor (biology)

For the drugs used in AIDS, please refer to protease inhibitor (pharmacology)

In biology and biochemistry, protease inhibitors are molecules that inhibit the function of peptidases (old name: protease, hence the term protease inhibitor). Many naturally-occurring protease inhibitors are proteins.

In medicine, protease inhibitor is often used interchangeably with alpha 1-antitrypsin (A1AT, which is abbreviated P_i for this reason)[1]. A1AT is indeed the protease inhibitor most often involved in disease, namely in alpha 1-antitrypsin deficiency.

Classes of protease inhibitors are:

• Cysteine protease inhibitors
• Serine protease inhibitors (serpins)
  • Trypsin inhibitors
• Threonine protease inhibitors