Viral and microbial proteases

Viral and microbial proteases are a diverse group of enzymes essential for the life cycle and pathogenicity of various infectious agents, including viruses, bacteria, and parasites (Wikipedia, 2024; NIH, 2022). These enzymes catalyze the hydrolysis of peptide bonds, often performing highly specific cleavages of polyproteins into functional mature proteins, a process critical for viral maturation and replication (UniProt, 2024; ResearchGate, 2025). In bacteria and parasites, proteases like the Caseinolytic protease (ClpP) complex or the 20S proteasome regulate protein turnover and stress responses, making them vital for survival within the host (NIH, 2021). Because these enzymes often possess unique substrate specificities distinct from human proteases, they serve as high-value targets for direct-acting antivirals and antibiotics (Frontiers, 2025). Clinically successful drugs, such as HIV and HCV protease inhibitors and the SARS-CoV-2 inhibitor nirmatrelvir, work by binding to the enzyme's active site to block its activity, thereby halting the production of infectious progeny (PubChem, 2024). However, the rapid evolution of these pathogens frequently leads to drug resistance through mutations, and achieving selectivity over host proteases remains a significant therapeutic challenge (ACS, 2021).

Other names

Viral proteasesMicrobial proteasesBacterial proteasesParasitic proteasesProtease inhibitors targetsPolyprotein processing enzymesHIV-1 proteaseHCV NS3/4A proteaseSARS-CoV-2 Main protease (Mpro)SARS-CoV-2 Papain-like protease (PLpro)Caseinolytic protease (ClpP)Bacterial signal peptidase

Inhibition of proteolytic activity by binding to the active site (competitive or covalent) or allosteric sites, preventing the cleavage of viral or microbial polyproteins into functional units, which halts replication and maturation.