Octaarginine

Octaarginine potently inhibits the chymotrypsin-like and caspase-like activities of purified rat skeletal muscle 20S proteasomes with IC₅₀ values of 100 nM and 200 nM, respectively, and weakly inhibits the trypsin-like activity; this inhibitory activity remains stable under physiological salt conditions^[1].
Octaarginine (up to 8 μM; 5-30 min) inhibits the activities of purified human erythrocyte 26S proteasomes and 20S/PA28 proteasome complexes, though with lower efficiency than for isolated 20S proteasomes^[1].
Octaarginine (30-60 μM; 2 h) inhibits chymotrypsin-like and caspase-like proteasome activities in cultured HeLa cells, leading to accumulation of ubiquitin-conjugated proteins, but does not significantly affect trypsin-like activity^[1].
Free Octaarginine peptide efficiently delivers protein, peptide, and plasmid DNA cargos into cultured cells, with stearylation of R8 significantly enhancing plasmid DNA transfection efficiency to match Lipofectamine levels^[2].
Octaarginine (3.9-7.9 nmol; 16 h) inhibits the growth of E. coli and S. aureus bacterial cells, reducing survival to 60% at 7.9 nmol (16 h incubation) and 40% at 3.9 nmol (16 h incubation), respectively^[4].
Octaarginine causes membrane damage and permeabilization in both E. coli and S. aureus bacterial cells^[4].
Octaarginine (5-30 nmol; 24 h) inhibits HeLa human cancer cell growth in a concentration-dependent manner, with maximum inhibition of 49% at 15 nmol (24 h incubation)^[4].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.