360325

Pepstatin A

• 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: 12352103

Properties

• optical activity: [α]20/D −90°, c = 0.3 in methanol
• mp: 233 °C (dec.) (lit.)
• 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

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.

Potent inhibitor of acid proteases, including pepsin, renin and cathepsin D and many microbial aspartic proteases. Effective concentration 1 μM. Stable for about 1 day.

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.