77170

Pepstatin A

≥100,000 U/mg

• Empirical Formula (Hill Notation): C₃₄H₆₃N₅O₉
• CAS Number: 26305-03-3
• Molecular Weight: 685.89
• Beilstein/REAXYS Number: 2201362
• EC Number: 247-600-0
• MDL number: MFCD00060740
• UNSPSC Code: 12352202
• PubChem Substance ID: 57652681
• NACRES: NA.77

Properties

• biological source: Streptomyces sp.
• Quality Level: 100
• form: powder
• specific activity: ≥100,000 U/mg
• mp: 233 °C (dec.) (lit.)
• solubility: ethanol: soluble 1 mg/mL
• storage temp.: 2-8°C
• SMILES string: CC(C)C[C@H](NC(=O)[C@H](C)NC(=O)C[C@H](O)[C@H](CC(C)C)NC(=O)[C@@H](NC(=O)[C@@H](NC(=O)CC(C)C)C(C)C)C(C)C)[C@@H](O)CC(O)=O
• InChI: 1S/C34H63N5O9/c1-17(2)12-23(37-33(47)31(21(9)10)39-34(48)30(20(7)8)38-27(42)14-19(5)6)25(40)15-28(43)35-22(11)32(46)36-24(13-18(3)4)26(41)16-29(44)45/h17-26,30-31,40-41H,12-16H2,1-11H3,(H,35,43)(H,36,46)(H,37,47)(H,38,42)(H,39,48)(H,44,45)/t22-,23-,24-,25-,26-,30-,31-/m0/s1
• InChI key: FAXGPCHRFPCXOO-LXTPJMTPSA-N

Description

Application

Pepstatin A is suitable for use:

• in the inhibitor cocktail in fluorometric matrix metalloproteinase assay
• as a protease inhibitor during homogenization of tissue
• as a protease inhibitor during extraction of cells
• to determine the molar concentrations of cathepsin D by titration with pepstatin A
• in inhibiting cathepsin D

It can be used in conjunction with E64-d and Leupeptin A to inhibit the degradation of autophagic cargo inside autophagosomes. For this application, the working concentration is typically between 1-10 μM.

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.

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)

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.

Other Notes

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

Safety Information

• Storage Class: 11 - Combustible Solids
• wgk_germany: WGK 2
• flash_point_f: Not applicable
• flash_point_c: Not applicable
• ppe: Eyeshields, Gloves, type N95 (US)