>4000 U/mg

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




specific activity

>4000 U/mg


H2O: 50 mg/mL

storage temp.


SMILES string




InChI key


Looking for similar products? Visit Product Comparison Guide

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.)

Unit Definition

1 U corresponds to the amount of inhibitor which reduces the trypsin activity by 1 BAEE-U. (1 BAEE-U is the amount of enzyme which increases the absorbance at 253 nm by 0.001 per minute at pH 7.6 and 25 °C; BAEE, Cat. No. 12880, as substrate)

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.

Other Notes

Inhibitor of trypsin, plasmin, papain and cathepsin B


13 - Non Combustible Solids

WGK Germany


Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Personal Protective Equipment

dust mask type N95 (US),Eyeshields,Gloves

Certificate of Analysis

Certificate of Origin

Leupeptins, new protease inhibitors from Actinomycetes.
T Aoyagi et al.
The Journal of antibiotics, 22(6), 283-286 (1969-06-01)
Biological activities of leupeptins.
T Aoyagi et al.
The Journal of antibiotics, 22(11), 558-568 (1969-11-01)
Structures and activities of protease inhibitors of microbial origin.
H Umezawa
Methods in enzymology, 45, 678-695 (1976-01-01)
A Kamal et al.
The Journal of cell biology, 142(4), 937-947 (1998-08-29)
Previously we reported that annexin VI is required for the budding of clathrin-coated pits from human fibroblast plasma membranes in vitro. Here we show that annexin VI bound to the NH2-terminal 28-kD portion of membrane spectrin is as effective as...
Susan E Logue et al.
Nature protocols, 4(9), 1383-1395 (2009-09-05)
Apoptosis is a mode of programmed cell death that is widely used to eliminate cells during development, tissue homeostasis, infection or in response to injury. Alterations to the plasma membranes of apoptotic cells trigger recognition and engulfment of such cells...

Our team of scientists has experience in all areas of research including Life Science, Material Science, Chemical Synthesis, Chromatography, Analytical and many others.

Contact Technical Service