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microbial, ≥90% (HPLC)

Acetyl-Leu-Leu-Arg-al, N-Acetyl-L-leucyl-L-leucyl-L-argininal hemisulfate salt, Leupeptin hemisulfate salt
Linear Formula:
C20H38N6O4 · 1/2H2SO4
CAS Number:
Molecular Weight:
MDL number:
PubChem Substance ID:

Quality Level

biological source



≥90% (HPLC)




H2O: 10 mM (Solutions are stable for a week at 4 °C. Stock solutions are stable up to 6 months at −20 °C.)
H2O: 50 mg/mL

storage temp.


SMILES string




InChI key


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General description

Leupeptin, or N-acetyl-L-leucyl-L-leucyl-L-argininal, is a naturally occurring tripeptide that acts particularly as a serine protease inhibitor and as a cysteine protease inhibitor. Its mechanism of action involves structurally similar covalent binding reactions:
  • In the active site of serine proteases, leupeptin forms a covalent hemiacetal adduct between the aldehyde group of leupeptin and the hydroxyl group of a serine residue in the enzyme active site.
  • In the active site of cysteine proteases, the electrophilic (aldehyde) carbon of leupeptin forms a comparable bond with the sulfur atom of a cysteine residue in the enzyme active site.


5, 10, 25, 50, 100, 250 mg in glass bottle

Biochem/physiol Actions

Inhibitor of serine and cysteine proteases. Inhibits plasmin, trypsin, papain, calpain, and cathepsin B. Does not inhibit pepsin, cathepsins A and D, thrombin, or α-chymotrypsin. Effective concentration 10-100 μM. There have been numerous studies using leupeptin to protect against hearing loss caused by acoustic overstimulation or the ototoxic antibiotic gentamicin. (Loss of cochlear hair cells is believed to be mediated by calpain.)

Analysis Note

Leupeptin gives multiple peaks on HPLC due to equilibria among three forms in solution. Purity determined using three main peaks. Majority of contaminating peptide is racemized leupeptin.

Storage Class Code

11 - Combustible Solids



Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

Certificate of Analysis

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Certificate of Origin

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Product Information Sheet

More Documents

Quotes and Ordering

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Analysis of mitochondrial function is central to the study of intracellular energy metabolism, mechanisms of cell death and pathophysiology of a variety of human diseases, including myopathies, neurodegenerative diseases and cancer. However, important properties of mitochondria differ in vivo and
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Journal of dairy science, 100(5), 4014-4024 (2017-03-13)
Adequate lipid synthesis by the mammary gland during lactation is essential for the survival of mammalian offspring. Cell death-inducing DNA fragmentation factor-α-like effector C (CIDEC) is a lipid droplet-associated protein and functions to promote lipid accumulation and inhibit lipolysis in
Philipp A Jaeger et al.
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ReadyShield Phosphatase and Protease Inhibitor Cocktail FAQ

ReadyShield® phosphatase and protease inhibitor cocktail FAQ for sample protection in a variety of cell types and tissue extracts, including mammalian, plant, and microbial samples. Our ReadyShield® Protease Inhibitor Cocktail is a non-freezing solution that contains inhibitors with a broad specificity for serine, cysteine, acid proteases and aminopeptidases.


MTP Activity Assay Kit Protocol

The MTP Activity Assay Kit is a sensitive, homogeneous fluorometric assay useful for continuous measurement of MTP activity in cell lysate or tissue homogenate.

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