Cysteine Proteases

Cysteine proteases (CPs) are present in all living organisms. More than twenty families of cysteine proteases have been described (Barrett, 1994) many of which (e.g. papain, bromelain, ficain , animal cathepsins) are of industrial importance. Recently, cysteine proteases, in particular lysosomal cathepsins, have attracted the interest of the pharmaceutical industry (Leung-Toung et al., 2002). Cathepsins are promising drug targets for many diseases such as osteoporosis, rheumatoid arthritis, arteriosclerosis, cancer, and inflammatory and autoimmune diseases. Caspases, another group of CPs, are important elements of the apoptotic machinery that regulates programmed cell death (Denault and Salvesen, 2002). Comprehensive information on CPs can be found in many excellent books and reviews (Barrett et al., 1998; Bordusa, 2002; Drauz and Waldmann, 2002; Lecaille et al., 2002; McGrath, 1999; Otto and Schirmeister, 1997).