Octaarginine 

Octaarginine is a cell-penetrating peptide and proteasome inhibitor. Octaarginine exhibits mixed-type inhibition against 20S proteasome chymotrypsin-like, caspase-like, and trypsin-like activities, and inhibits 26S proteasome activity with decreased efficiency. Octaarginine induces ubiquitin-conjugated protein accumulation, mediates HSPG-dependent cellular internalization via macropinocytosis, enhances liposomal cargo uptake and gene delivery. Octaarginine can be used for the research of cervix carcinoma, collagen antibody-induced arthritis, and bacterial infections^[1][2][3][4].

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.

Rhodamine-labeled Octaarginine (R8) (20 μL of 0.1 mM; intra-articular injection; single dose) shows the highest articular cartilage matrix binding efficiency among tested polyarginine peptides^[3].
Rhodamine-labeled octaarginine (R8) (20 μL of 0.1 mM; intra-articular injection; single dose) accumulation is significantly decreased in the degenerative articular cartilage of CAIA mice, reflecting loss of chondroitin sulfate proteoglycans^[3].

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

1267.50

C₄₈H₉₈N₃₂O₉

148796-86-5

Arg-Arg-Arg-Arg-Arg-Arg-Arg-Arg

RRRRRRRR

Room temperature in continental US; may vary elsewhere.

Please store the product under the recommended conditions in the Certificate of Analysis.

• [1]. Kloss A, et al. The cell-penetrating peptide octa-arginine is a potent inhibitor of proteasome activities. Eur J Pharm Biopharm. 2009;72(1):219-225.  [Content Brief]

  [2]. Khalil IA, et al. Octaarginine-modified liposomes: enhanced cellular uptake and controlled intracellular trafficking. Int J Pharm. 2008;354(1-2):39-48.  [Content Brief]

  [3]. Inagawa K, et al. Optical imaging of mouse articular cartilage using the glycosaminoglycans binding property of fluorescent-labeled octaarginine. Osteoarthritis Cartilage. 2009;17(9):1209-1218.  [Content Brief]

  [4]. Ratrey P, et al. Enhancing Aqueous Solubility and Antibacterial Activity of Curcumin by Complexing with Cell-Penetrating Octaarginine. ACS Omega. 2020;5(30):19004-19013. Published 2020 Jul 23.  [Content Brief]