autoproteolytic

Autoproteolytic refers to the cleavage of peptide bonds performed by a protein on itself or within the same molecule. Autoproteolysis can be intramolecular, where a single polypeptide cleaves its own backbone, or intermolecular, where one copy cleaves another identical chain. In many contexts the term describes autocatalytic maturation or activation of enzymes that are initially synthesized as inactive precursors or as parts of larger polyproteins.

Mechanistically, autoproteolysis commonly relies on intrinsic catalytic residues located in the protein’s active site, such as serine, cysteine, or aspartate, and may require conformational changes or metal ions. The reaction is self-generated and does not require another enzyme in the immediate vicinity. Autoproteolytic events can serve to activate proteins, release functional domains, or reorganize a protein’s structure to enable activity.

Biological roles include activation of zymogens and maturation of viral polyproteins. For example, HIV-1 protease is produced as part of a larger polyprotein and becomes active through autoproteolytic processing. Autoproteolysis also occurs in other viral and cellular proteins to regulate function, localization, or interactions. In addition, inteins are genetic elements that catalyze self-excision from host proteins and join the surrounding sequences in a process often described as protein splicing, a related autoproteolytic phenomenon.

Autoproteolysis can pose challenges in research and biotechnology. Unintended cleavage can destabilize proteins or complicate purification and structural studies. Conversely, engineered autoproteolytic sites are used to achieve controlled activation, remove affinity tags, or implement self-cleaving linkers in molecular biology applications.