Endoprotease

An endoprotease, also known as an endopeptidase, is a type of enzyme that catalyzes the hydrolysis of peptide bonds within the interior of polypeptide chains. Unlike exoproteases, which cleave amino acids from the ends of polypeptides, endoproteases act at specific sites within the protein molecule, leading to the cleavage of larger peptides into smaller fragments.

Endoproteases play essential roles in various biological processes, including protein digestion, cellular regulation, and protein maturation. They are classified according to their catalytic mechanisms into several categories, including serine proteases, cysteine proteases, aspartic proteases, and metalloproteases. Each class operates through distinct active site configurations and mechanisms.

In digestion, endoproteases such as pepsin, trypsin, and chymotrypsin break down dietary proteins into smaller peptides that can be further degraded into amino acids for absorption. In cellular processes, they are involved in protein turnover, activating or inactivating enzymes and hormones through specific cleavage.

Endoproteases are utilized in biotechnology and medicine for applications such as protein sequencing, the production of bioactive peptides, and the development of therapeutic agents. For example, protease inhibitors targeting specific endoproteases are used in treating diseases involving proteolytic dysregulation.

Structural features of endoproteases include a catalytic site that specifically recognizes peptide bonds and an active site that binds to substrate molecules. Their activity is often regulated by pH, cofactors, and inhibitors, which modulate their function in various biological contexts. Overall, endoproteases are vital enzymes that facilitate precise protein processing and function across living organisms.