Description
E-64 (66701-25-5) is a cell-permeable, epoxysuccinyl peptide irreversible inhibitor of calpain and other cysteine proteases.1,2Inhibits calpain-dependent apoptosis pathway in T cells3but promotes heat-induced apoptosis in FM3A cells. Typical working concentration is 0.5-10 μg/ml.4
Uses
It is used as a broad spectrum cysteine proteinase and calpain activation inhibitor. Additionally, Prevotella intermediate studies report that E-64 blocks the breakdown of methaemoglobin and the oxidation of oxyhaemoglobin by InpA. E-64 has also been used to study excystation in Giardia lamblia. E-64 is an inhibitor of Calpain, cathepsin K and cathepsin S. 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
Definition
ChEBI: E64 is an epoxy monocarboxylic acid, a dicarboxylic acid monoamide, a member of guanidines and a L-leucine derivative. It has a role as a protease inhibitor, an antimalarial and an antiparasitic agent. It is a tautomer of an E64 zwitterion.
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
Hazard
A reproductive hazard.
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.
Background
The small-molecule E-64 is an anti-parasitic and anti-malarial agent that acts as an irreversible, non-selective inhibitor of cysteine proteases. E-64 binds and inhibits the cysteine proteases cathepsin K, cathepsin S, and cathepsin L in human osteoclast assays. E-64 also inhibits other proteases, including cathepsin B, cathepsin H, papain, and calpain. Exposure of filarial parasites to E-64 inhibited cathepsin B and resulted in decreased parasite motility and viability. E-64 effectively inhibited a SUMO-1-like cysteine protease from the African swine fever virus, resulting in impaired viral replication and a possible treatment for a viral disease that typically causes high mortality in domestic pigs. Inhibition of cathepsin B by E-64 in tumor cell lines reduced the invasive properties of the cells by 75%. E-64 treatment of ischemia-reperfusion rat kidneys blocked calpain activity and reduced several markers of renal dysfunction.
References
[1] K K WANG P W Y. Calpain inhibition: an overview of its therapeutic potential.[J]. Trends in pharmacological sciences, 1994, 15 11: 412-419. DOI:
10.1016/0165-6147(94)90090-6[2] A J BARRETT. L-trans-Epoxysuccinyl-leucylamido(4-guanidino)butane (E-64) and its analogues as inhibitors of cysteine proteinases including cathepsins B, H and L.[J]. Biochemical Journal, 1982, 201 1: 189-198. DOI:
10.1042/bj2010189[3] A SARIN. Inhibition of activation-induced programmed cell death and restoration of defective immune responses of HIV+ donors by cysteine protease inhibitors.[J]. Journal of immunology, 1994, 153 2: 862-872.
[4] WEI-GUO ZHU . Promotion of Heat-Induced Apoptosis in FM3A Cells by Protease Inhibitors[J]. Biochemical and biophysical research communications, 1996, 225 3: Pages 924-931. DOI:
10.1006/bbrc.1996.1273
