Proteolytic enzymes are enzymes that cleave peptide bonds in proteins or peptides, producing shorter chains or releasing terminal residues. They participate in controlled protein processing as well as degradation, with substrate recognition directing cleavage toward particular bonds [1][2]. Proteases can operate in cascades in which activation of one enzyme initiates successive cleavage events in other proteins [3]. Their cellular localization restricts which substrates they encounter; extracellular proteases act on matrix components and signaling proteins within the surrounding tissue environment [4]. Catalytic groups include nucleophilic amino acid side chains or metal-associated water molecules. Cysteine proteases such as caspases combine an active-site cysteine with recognition of particular substrate residues. Regulation of enzyme activation, access, and inhibition determines when the corresponding proteolytic reactions occur [1][5].
Protein Degradation and Inhibitors·Molecular Biology·Biochemistry, Genetics and Molecular Biology·Life Sciences