Proteólisi

Proteólisi, or proteolysis, is the enzymatic breakdown of proteins into smaller polypeptides or amino acids. It occurs by hydrolysis of peptide bonds and is essential for digestion, protein turnover, and regulation of cellular processes.

Proteases are grouped by catalytic mechanism and substrate action. Endopeptidases cleave within peptide chains (trypsin, chymotrypsin, pepsin); exopeptidases remove residues from the ends (carboxypeptidases). Major enzyme families include serine, cysteine, aspartic, and metalloproteases.

In humans, proteolysis takes place in the digestive tract, lysosomes, and the cytosol via the ubiquitin–proteasome system. Roles include digestion of dietary proteins, activation and inactivation of hormones, antigen processing, extracellular matrix remodeling, and participation in apoptosis via caspases.

Protease activity is tightly regulated by zymogen activation, inhibitors, and cellular compartmentalization. Dysregulation can contribute to diseases such as pancreatitis, cancer invasion, and neurodegeneration. Understanding proteolysis informs basic biology and the development of therapeutic inhibitors and modulators.