Pepstatin A (Microbial)

Pepstatin A is used as a protease inhibitor. Pepstatin forming a 1:1 complex with the carboxylproteases (acid proteases) bovine chymosin, cathepsin D, pepsin, protease B and renin. The inhibitor is highly selective and does not inhibit thiol proteases, neutral proteases or serine proteases. Solublized gamma-secretase and retroviral protease are also inhibited by Pepstatin A. It has been used to characterize proteases from several sources. Pepstatin A is thought to inhibit by a collected- substrate inhibition mechanism. Pepstatin A is often used as a component in a final mixture with other inhibitors (protease Inhibitor cocktails). One recommended set of stock solution concentrations is: bestatin (1.7mM, selective for aminopeptidase), E-64 (0.22mM, for cysteine proteases), Pepstatin A (2.5mM, for aspartyl proteases), AEBSF (18mM, for serine proteases) and disodium EDTA (86mM, for metalloproteases) , Synonyms:, H-Iso-Va, CAS Number: 26305-03-3, Molecular Formula: C34H63N5O9, Molecular Weight: 685.9, Appearance: White powder, Purity: ~90%, Amino Acid Sequence: H-Iso-Valeryl-Val-Val-Statine-Ala-4-Statine (Statine: 4-Amino-3-hydroxy-6-methyl heptanoic acid), Working Concentration: 0.5-1ug/ml, Solubility: Soluble in either DMSO or ethanol:glacial acetic acid (9:1) at 1mg/ml. Aqueous buffer at slightly alkaline pH is recommended for dilution of the reconstituted protein in either the above organic solvents. Note: Insoluble in dH2O and other aqueous buffer at near neutral pH. If water or acidic buffer is used for diluion, Pepstain A may precipitate from the soluion. Solutions of Pepstatin A can be heated as high as 60°C without any decomposition of the peptide. Preparation Instructions: Pepstatin A is only sparingly soluble in water., The solubility of Pepstatin A is related to the purity of the preparation. Solutions of Pepstatin A can be heated as high as 60°C without any decomposition of the peptide. The recommended procedure is to include acetic acid., Stock solutions at 1mg/mL should be stable at least a week at 4°C. A 1mM solution in methanol should be stable for months at -20°C. If solutions become more yellow the reagent is hydrolyzing., An effective working concentration is 1uM, stable for at least one day at room temperature., A typical working concentration is 0.5-1ug/ml. Storage and Stability: Lyophilized powder may be stored desiccated at -20°C. Aliquot and store at -20°C after reconstitution. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.