Protease Background

What is a protease?
A protease, also called proteinase or proteolytic enzyme, is a protein molecule that can cleave the peptide bonds linking adjacent amino acids in a protein or peptide. Consequently, proteases are sometimes referred to as "molecular scissors." Like other enzymes, proteases are catalysts - a single protease molecule can cleave hundreds to thousands of peptide bonds per minute.

Proteases have been well characterized both structurally and biochemically. The first proteases that were characterized were powerful digestive enzymes that could degrade virtually any protein substrate. Over the past thirty years, however, it has become increasingly clear that the protease gene family contains members with widely divergent properties, including exquisitely specific proteases that target only a single protein in the human body. It has also become apparent that the use of proteases to regulate key biological processes and pathways is a recurring theme in Nature.

The rapidly evolving area of genomic sciences has demonstrated that proteases are among the largest gene family found in Nature, constituting between 2-5% of every genome sequenced to date. For example, approximately 2.5% of human genes appear to encode proteases. Consistent with the important and widespread role of proteases in human biology and pathology, human proteases have been validated as therapeutic targets both for inhibitors and agonists and have also been used as therapeutic agents. Examples of natural proteases that are used in the clinic include Factor VIIa and Factor IX for inherited hemophilia, tissue-type plasminogen activator (Activase) to dissolve clots in heart attacks, activated protein C (Xigris) for sepsis, and Botox for cosmetic use.