Endopeptidaasi

Endopeptidaasi is a type of enzyme that catalyzes the hydrolysis of internal peptide bonds within a protein or polypeptide chain. Unlike exopeptidases, which cleave amino acids from the terminal ends of a peptide, endopeptidases break peptide bonds within the polypeptide backbone. This action can lead to the fragmentation of larger proteins into smaller peptides or individual amino acids.

Endopeptidases are crucial in numerous biological processes. In digestion, they are essential for breaking down dietary proteins into smaller peptides and amino acids that can be absorbed by the body. Examples include trypsin, chymotrypsin, and pepsin, found in the digestive tracts of animals.

Beyond digestion, endopeptidases play significant roles in cellular regulation. They are involved in protein turnover, the activation or inactivation of precursor proteins (proenzymes), and the processing of signaling molecules. For instance, caspases are a family of endopeptidases critical for apoptosis, or programmed cell death. Metalloproteinases, a class of endopeptidases requiring metal ions for activity, are involved in processes such as extracellular matrix remodeling and tissue development.

The specificity of an endopeptidase is determined by the amino acid residues surrounding the cleavage site. Different endopeptidases recognize and cleave specific sequences, contributing to their diverse biological functions. The activity of endopeptidases can be regulated by various factors, including pH, temperature, and the presence of inhibitors or activators.