Proteaasien

Proteaasien are enzymes that catalyze the hydrolysis of peptide bonds in proteins. They are found in all living organisms and play essential roles in digestion, protein turnover, and regulatory processes. Proteases vary in their preferred substrates, subcellular location, and physiological function; some act outside cells to digest dietary proteins, while others function inside organelles or the cytosol, degrading misfolded or damaged proteins.

Proteases are commonly classified by their catalytic mechanism into several families: serine proteases (such as trypsin and chymotrypsin) use a catalytic serine; cysteine proteases use a catalytic cysteine; aspartic proteases use two aspartate residues; metalloproteases require a metal ion, typically zinc. There are also threonine proteases, such as those in the proteasome. Proteases can be endopeptidases, which cleave peptide bonds within a protein, or exopeptidases, which trim amino acids from the ends of polypeptide chains.

Most proteaasien are synthesized as inactive precursors (zymogens) and become active upon proteolytic processing. Activity is tightly regulated by endogenous inhibitors, pH, and subcellular localization. Misregulation of proteolysis can contribute to disease, making proteases and their inhibitors important in medical research.

Proteaasien have numerous applications in industry and research. In food and nutrition, digestive proteases aid protein digestion; in detergents, proteases enable stain removal; and in proteomics, proteases such as trypsin are used to digest proteins prior to mass spectrometry analysis. In medicine, proteases and their inhibitors are targets for therapies, including HIV protease inhibitors and proteasome inhibitors used in cancer treatment.