Proteases are known to regulate multiple aspects of protein’s life viz., protein’s fate, localization, and activity, modulation of protein-protein interactions, creation of new bioactive molecules, contribution to the processing of cellular information, and in the generation, transduction, and amplification of molecular signals. Any alterations in the essential roles of proteases subjects to multiple pathological conditions such as cancer, neurodegenerative disorders, and inflammatory and cardiovascular diseases. Proteases cleave peptide bonds being N-terminal (for aminopeptidases), internal (for endopeptidases), and C-terminal (for carboxypeptidases). Carbonyl group of the substrate peptide bond is polarized by all the proteases stabilizing the oxyanion hole oxygen, which leads to the increased susceptibility of carbon to be attacked by an activated nucleophile. This is accomplished by four ways, and hence receives the names of four catalytic classes: aspartic proteases, cysteine proteases, metalloproteases, serine proteases. The modern system provides the five groups of classification of proteases- aspartic, cysteine, metallo, serine, and threonine.

Dinesh Gupta lab Translational bioinformatics group, ICGEB, New Delhi, India