Proteasome Inhibitors Available from Peptides International

Proteasome Inhibitors and Substrates Available from Peptides International
Peptide Aldehydes (MG 132, MG 115, and PSI), Lactacystin, and Epoxomicin are popular proteasome inhibitors that are manufactured by the Peptide Institute and available from Peptides International in our Louisville facility. Please contact us to receive additional information about these and related products.
Proteasome Inhibitors Proteasomes are responsible for the selective degradation of proteins when cells no longer need them. Inhibiting proteasomes in cancer cells can disrupt protein regulation, which ultimately can lead to apoptosis or programmed cell death. The peptide aldehydes, MG 132, MG 115, and PSI, inhibit the complex's chymotrypsin-like activity in a potent but reversible manner. Lactacystin is a natural, irreversible, nonpeptide, cell permeable inhibitor that is more selective than peptide aldehydes but less selective than peptide boronates, another class of proteasome inhibitors. Epoxomicin, originally isolated from a species of Actinomycetes, is cell-permeable, irreversible and relatively selective proteasome inhibitor. It is more potent than lactacystin and inhibits the chymotrypsin-like, trypsin-like, and peptidylglutamyl peptide-hydrolyzing activities of the proteasome. Epoxoketones, such as epoxomicin, are the most selective because they not only react with the hydroxyl group but also the N-terminal threonine at the proteasome's active site. Current research efforts are aimed at evaluating the efficacy of epoxomicin in mouse models of myeloma and could prove valuable as an anticancer therapy.

Proteasome Review Article of Interest The proteasome is a multisubunit complex responsible for the degradation of almost all cytosolic proteins. The role of the proteasome in antigen presentation was reviewed by Matthew Bogyo et al (1) in 1997. This review contains 73 references and proposes possible mechanisms for inactivation by proteasomal inhibitors such as lactacystin. C-terminal peptide aldehydes were the first of several classes of compounds to be investigated as proteasome inhibitors. These inhibitors are cell-permeable and block proteasome function without affecting normal biological processes such as ATP metabolism and protein synthesis. 1. M. Bogyo, M. Gaczynska and H. L. Ploegh, Biopoly., 43, 269-280 (1997).

CODE	PRODUCT DESCRIPTION	VIAL	USD
Proteasome Inhibitors
IEP-4381-v	Epoxomicin (2R)-2-[Acetyl-(N-Methyl-L-Isoleucyl)-L-Isoleucyl-L- Threonyl-L-Leucyl]-2-Methyloxirane (M.W. 554.72 ) C₂₈H₅₀N₄O₇ Inhibitor for Proteasome Synthetic Product Epoxomicin is a cell permeable, potent, and selective proteasome inhibitor, more potent than lactacystin.	0.2 mg vial	219

ILC-4368-v	Lactacystin N-Acetyl-L-Cysteine, S-[2R,3S,4R]-3-Hydroxy-2-[(1S)-1-Hydroxy-2-Methylpropyl]-4-Methyl-5-Oxo-2-Pyrolidinecarbonyl] (M.W. 376.43) C₁₅H₂₄N₂O₇S Inhibitor for Proteasome Microbial Product Lactacystin is a natural, irreversible, nonpeptide, cell permeable inhibitor that is more selective than peptide aldehydes but less selective than peptide boronates.	0.2 mg vial	195

IAT-3169-v	Z-Ile-Glu(OtBu)-Ala-Leu-H *[PSI]* Benzyloxycarbonyl-L-Isoleucyl-Gamma-t-Butyl-L-Glutamyl-L-Alanyl-L-Leucinal (M.W. 618.77) C₃₂H₅₀N₄O₈ Inhibitor for Proteasome Synthetic Product Peptide aldehydes, such as Z-Ile-Glu(OtBu)-Ala-Leu-H, inhibit the chymotrypsin-like activity in a potent but reversible manner.	5 mg vial	83

IZL-3175-v	Z-Leu-Leu-Leu-H [MG 132] [MG132] Benzyloxycarbonyl-L-Leucyl-L-Leucyl-L-Leucinal (M.W. 475.63) C₂₆H₄₁N₃O₅ Inhibitor for Proteasome Synthetic Product Peptide aldehydes, such as Z-Leu-Leu-Leu-H, inhibit the chymotrypsin-like activity in a potent but reversible manner.	5 mg vial	43

IZL-3170-v	Z-Leu-Leu-Nva-H [MG 115] [MG115] aka Z-LL-Nva-H Z-LLNva-CHO Benzyloxycarbonyl-L-Leucyl-L-Leucyl-L-Norvalinal (M.W. 461.60) C₂₅H₃₉N₃O₅ Inhibitor for Proteasome Synthetic Product Peptide aldedydes, such as Z-Leu-Leu-Nva-H, inhibit the chymotrypsin-like activity in a potent but reversible manner.	5 mg vial	55

Proteasome Substrates
MLL-3177-v	Z-Leu-Leu-Leu-MCA aka Z-Leu-Leu-Leu-AMC Z-LLL-AMC Benzyloxycarbonyl-L-Leucyl-L-Leucyl-L-Norvaline 4-Methyl-Coumaryl-7-Amide (M.W. 648.79) C₃₆H₄₈N₄O₇ Substrate for Proteasome s. Tsubuki, et al. Biochem. Biophys. Res. Commun., 196, 1195 (1993).	5 mg vial	55
MLG-3179-v	Z-Leu-Leu-Glu-MCA aka Z-Leu-Leu-Glu-AMC Benzyloxycarbonyl-L-Leucyl-L-Leucyl-L-Glutamic Acid 4-Methyl-Coumaryl-7-Amide (M.W. 648.79) C₃₆H₄₈N₄O₇ Substrate for Proteasome Post-glutamyl peptidyl hydrolytic-like activity of the proteasome	5 mg vial	65
Please note: Carbobenzoxy (Cbz) = Benzyloxycarbonyl (Z) protecting group in peptide chemistry
Please contact Peptides International for ordering information. Peptides International, Inc. PO Box 24658 Louisville, Kentucky 40224 USA Phone: 502-266-8787 or 800-777-4779 Fax: 502-267-1FAX (1329) Email: peptides@pepnet.com
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