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Cat.No. 4045 - PSI | C32H50N4O8 | CAS No. 158442-41-2
Description: Proteasome inhibitor. Also prevents activation of NF-κB
Chemical Name: N-[(Phenylmethoxy)carbonyl]-L-isoleucyl-L-α-glutamyl-tert-butyl ester-N-[(1S)-1-formyl-3-methylbutyl]-L-alaninamide
Purity: ≥90% (HPLC)

Biological Activity

Proteasome inhibitor; inhibits chymotrypsin-like activity of the proteasome. Causes dopaminergic cell death in vitro. Prevents activation of NF-κB in response to TNF-α and okadaic acid (Cat. No. 1136) by inhibiting IκB-α degradation. Also inhibits NO production by LPS-activated macrophages.

Technical Data

M. Wt 618.77
Formula C32H50N4O8
Storage Store at -20°C
Purity ≥90% (HPLC)
CAS Number 158442-41-2
PubChem ID 9960660
Smiles [H]C([C@H](CC(C)C)NC([C@H](C)NC([C@H](CCC(OC(C)(C)C)=O)NC([C@H]([C@@H](C)CC)NC(OCC1=CC=CC=C1)=O)=O)=O)=O)=O

The technical data provided above is for guidance only. For batch specific data refer to the Certificate of Analysis.

All Tocris products are intended for laboratory research use only.

Solubility Data

Solvent Max Conc. mg/mL Max Conc. mM
DMSO 18.56 30

Preparing Stock Solutions

The following data is based on the product molecular weight 618.77. Batch specific molecular weights may vary from batch to batch due to solvent of hydration, which will affect the solvent volumes required to prepare stock solutions.

Select a batch to recalculate based on the batch molecular weight:
Concentration / Solvent Volume / Mass 1 mg 5 mg 10 mg
1 mM 1.62 mL 8.08 mL 16.16 mL
5 mM 0.32 mL 1.62 mL 3.23 mL
10 mM 0.16 mL 0.81 mL 1.62 mL
50 mM 0.03 mL 0.16 mL 0.32 mL

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Product Datasheets

Safety Datasheet


References are publications that support the products' biological activity.

Traenckner et al (1994) A proteasome inhibitor prevents activation of NF-κB and stabilizes a newly phosphorylated form of IκB-α that is still bound to NF-κB. EMBO J. 13 5433 PMID: 7957109

Bukhatwa et al (2009) An immunohistochemical and stereological analysis of PSI-induced nigral neuronal degeneration in the rat. J.Neurochem. 109 52 PMID: 19187437

Griscavage et al (1996) Inhibitors of the proteasome pathway interfere with induction of nitric oxide synthase in macrophages by blocking activation of transcription factor NF-κB. Proc.Natl.Acad.Sci.USA 93 3308 PMID:

If you know of a relevant reference for PSI, please let us know.

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Keywords: PSI, supplier, proteasome, inhibitors, inhibits, Nuclear, Factor, Kappa, B, NF-κB, NF-kappaB, NF-kB, activation, Proteasome, NF-kB/IkB, Proteasome, Tocris Bioscience

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Pathways for PSI


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