E3132

E-64

protease inhibitor

• Synonym(s): trans-Epoxysuccinyl-L-leucylamido(4-guanidino)butane, L-trans-3-Carboxyoxiran-2-carbonyl-L-leucylagmatine, N-(trans-Epoxysuccinyl)-L-leucine 4-guanidinobutylamide
• Empirical Formula (Hill Notation): C₁₅H₂₇N₅O₅
• CAS Number: 66701-25-5
• Molecular Weight: 357.41
• Beilstein: 1405664
• MDL number: MFCD00080261
• UNSPSC Code: 12352202
• PubChem Substance ID: 24278411
• NACRES: NA.77

Properties

• biological source: synthetic (organic)
• Assay: ≥98% (HPLC)
• form: powder
• solubility: water: 20 mg/mL, clear, colorless to faintly yellow
• storage temp.: 2-8°C
• SMILES string: CC(C)C[C@H](NC(=O)[C@@H]1O[C@H]1C(O)=O)C(=O)NCCCCNC(N)=N
• InChI: 1S/C15H27N5O5/c1-8(2)7-9(20-13(22)10-11(25-10)14(23)24)12(21)18-5-3-4-6-19-15(16)17/h8-11H,3-7H2,1-2H3,(H,18,21)(H,20,22)(H,23,24)(H4,16,17,19)/t9-,10+,11+/m0/s1
• InChI key: LTLYEAJONXGNFG-HBNTYKKESA-N

Description

General description

E-64 is a cysteine protease inhibitor that was isolated from the mold Aspergillus japonicus TPR-64. E-64 is also known as N-[N-(L-3-trans-carboxyoxiran-2-carbonyl)-L-leucyl]-agmatine. E-64 effectively inhibits various cysteine proteases, in particular:

• cathepsin K
• cathepsin L
• cathepsin S

E-64 also acts against other enzymes, such as:

• calpain
• cathepsin B
• cathepsin H
• papain

Application

E-64 is an effective ligand for affinity purification of cysteine proteases. When coupled to a thiolated affinity matrix, binding is no longer irreversible, but specificity is retained.

Biochem/physiol Actions

E-64 is an irreversible, potent, and highly selective cysteine protease inhibitor. E-64 does not react with the functional thiol group of non-protease enzymes, such as L-lactate dehydrogenase or creatine kinase. E-64 will not inhibit serine proteases (except trypsin) like other cysteine protease inhibitors, leupeptin and antipain. The trans-epoxysuccinyl group (active moiety) of E-64 irreversibly binds to an active thiol group in many cysteine proteases, such as papain, actinidase, and cathepsins B, H, and L to form a thioether linkage. E-64 is a very useful cysteine protease inhibitor for use in in vivo studies because it has a specific inhibition, it is permeable in cells and tissues and has low toxicity.

Preparation Note

E-64 is soluble in water. A 20 mg/ml solution can be prepared in water (heat may be needed). A suggested stock solution is a 1 mM aqueous solution. The effective concentration for use as a protease inhibitor is 1 to10 μM. Aqueous stock solutions are stable for months at -20 °C. Diluted solutions are stable for days at neutral pH. E-64 is stable from pH 2-10, but is unstable in ammonia or in HCl. E-64 is also soluble in DMSO, a 10 mM solution can be prepared in dry DMSO and stored at -20 °C. Subsequent dilutions were in culture medium. Solutions for injection were prepared by dissolving E-64 in 0.9% sodium chloride or in a minimum amount of saturated sodium bicarbonate followed by dilution with 0.9% sodium chloride (after adjusting the pH to 7.0 with acetic acid).

Safety Information

• Storage Class Code: 11 - Combustible Solids
• WGK: WGK 3
• Flash Point(F): Not applicable
• Flash Point(C): Not applicable
• Personal Protective Equipment: dust mask type N95 (US), Eyeshields, Gloves