Proteolytic

Proteolytic is an adjective relating to proteolysis, the breakdown of proteins into smaller peptides and amino acids by proteases. Proteolysis is a fundamental biological process that occurs in digestion, protein turnover, and the regulation of various cellular functions. It involves endoproteolysis, which cleaves internal peptide bonds, and exopeptidase activity, which trims amino acids from peptide ends.

Proteases, or proteolytic enzymes, catalyze these reactions. They are broadly categorized by catalytic mechanism, including serine proteases (such as trypsin and chymotrypsin), cysteine proteases, aspartic proteases, metalloproteases, and threonine proteases. Many proteases are produced as inactive precursors called zymogens and require specific cues to become active. Their activity is often tightly regulated by pH, inhibitors, compartmentalization, and substrate availability.

Proteolysis serves numerous roles: digestive proteases break down dietary proteins in the gut; intracellular proteolysis degrades damaged or obsolete proteins and generates peptides for major histocompatibility complex (MHC) antigen presentation; extracellular proteases remodel tissues and regulate signaling by processing receptors or ligands. Proteolysis also contributes to protein maturation, activation of hormones, and peptide signaling.

Disruption of proteolytic balance can contribute to disease, including inflammatory and degenerative disorders, cancer invasion, and viral infections. Protease inhibitors and protease-targeted therapies form important classes of drugs. In research and industry, controlled proteolysis is exploited for protein identification in proteomics and for production processes such as cheese making and other processed foods.