77170 Sigma-Aldrich

Pepstatin A

≥100,000 U/mg

  • CAS Number 26305-03-3

  • Empirical Formula (Hill Notation) C34H63N5O9

  • Molecular Weight 685.89

  •  Beilstein Registry Number 2201362

  •  EC Number 247-600-0

  •  MDL number MFCD00060740

  •  PubChem Substance ID 57652681



Related Categories Biochemicals and Reagents, Enzyme Inhibitors, Enzyme Inhibitors by Type, Enzymes, Inhibitors, and Substrates, Substrate Analogs More...
mp   233 °C (dec.) (lit.)
storage temp.   2-8°C


Other Notes

Strong inhibitor of acid proteases - pepsin, cathepsin D, renin

Preparation Note

Pepstatin can be dissolved at 1 mg/ml in 10% (v/v) acetic acid in methanol (9:1 methanol:acetic acid). The inclusion of acetic acid may be necessary to dissolve this peptide in methanol or DMSO. It has been dissolved at 1 to 2 mg/ml in ethanol, but heat may be required for complete dissolution. Solutions of Pepstatin A can be heated as high as 60 °C without any decomposition of the peptide.
Stock solutions at 1 mg/ml are stable at least a week at 4 °C. A 1 mM solution in methanol or DMSO is stable for months at -20 °C. If solutions become darker yellow, the reagent is hydrolyzing.
A working concentration of 1 μM is stable for at least one day at room temperature.

Unit Definition

1 U corresponds to the amount of inhibitor which reduces the activity of pepsin by 1 U (1 U corresponds to the amount of enzyme which increases the absorbance at 280 nm by 0.001 per minute at pH 2.0 and 37°C (Hemoglobin, Cat. No. 51290, as substrate, in an endvolume of 16 ml)); 10′000 absorbance-U as described above are equivalent to ∼1 Bergmeyer-U (when 1 pepsin-U is the amount of enzyme which hydrolyzes 1 μmol acetyl-L-phenylalanyl-3,5-diiodo-L-tyrosin per minute at pH 2.0 and 37°C)

Biochem/physiol Actions

Pepstatin A is an inhibitor of acid proteases (aspartyl peptidases). It forms a 1:1 complex with proteases such as pepsin, renin, cathepsin D, bovine chymosin, and protease B (Aspergillus niger). The inhibitor is highly selective and does not inhibit thiol proteases, neutral proteases, or serine proteases. Solubilized γ-secretase and retroviral protease are also inhibited by Pepstatin A. It has been used to characterize proteases from several sources.

Safety & Documentation

Safety Information

NONH for all modes of transport
WGK Germany 


Certificate of Analysis

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Peer-Reviewed Papers


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