Proteases: Nature’s Destroyers and the Drugs that Stop Them

Proteases are found in all life forms. Initially proteases were described from gastric juices and thought to be involved in nonspecific degradation of proteins. While some proteases are nonspecific, others are highly specific both in their substrate selection and cleavage recognition sites. Proteases account for ~2% of the human genome with 553 defined members [1,2] and 1-5% of the genomes in infectious organisms such as bacteria, parasites and viruses [3]. Proteases regulate many cellular processes, such as protein degradation [4,5], digestion [6,7] blood coagulation [8], wound healing [9], ovulation [10], embryonic development [11], bone formation [12], neuronal outgrowth [13], cell-cycle regulation [14], immune and inflammatory response [15], angiogenesis [16] and apoptosis [17]. Proteases are viable drug targets because of their role in cellular functions of both mammalian cells and pathogens.