26305-03-3

Pepstatin A is a bacterial-derived chemotactic pentapeptide that irreversibly inhibits aspartic proteases, including pepsin, gastricsin, renin, cathepsin E, and cathepsin D. Pepstatin A has been reported to stimulate human neutrophil degranulation (EC₅₀ = 0.75 μM) and super oxide production (EC₅₀ = 1.5 μM). Pepstatin A has been widely used as a research tool in studies of protease mechanisms and biological functions and has been examined as a therapeutic agent for inflammatory conditions including gastric ulcer, edema, and hypertension.

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Antiviral;Aspartic proteases irreversible inhibitor

As an aspartic proteases irreversible inhibitor, Pepstain A can be used in conjunction with E64-d and Leupeptin A to inhibit the degradation of autophagic cargo inside autophagosomes.

ChEBI: Pepstatin A is a pentapeptide isolated from Streptomyces testaceus. It is a potent inhibitor of aspartyl proteases. It has a role as a bacterial metabolite and an EC 3.4.23.* (aspartic endopeptidase) inhibitor. It is a pentapeptide and a secondary carboxamide. It is a conjugate acid of a pepstatin A(1-).

Primary Targetaspartic proteases

Moderately toxic by intraperitoneal route. When heated to decomposition it emits toxic fumes of NOx.

This naturally occurring statine-containing peptidomimetic (FWfree-acid = 685.90 g/mol; CAS 26305-03-3), also called pepstatin A and isovalerylpepstatin and named systematically as N-(isovaleryl)-L-valyl-L-valyl-statylL-alanyl-statine (where the statyl residue is a (3S,4S)-4-amino-3-hydroxy-6- methylheptanoyl residue and the C-terminal statine is the corresponding acid), is a presumptive transition-state analogue for prototypical aspartate proteinase pepsin (Ki = 46 pM). Pepstatin will also inhibit other carboxy proteinases. The inhibitory effectiveness of statine-containing peptides has been widely exploited by incorporating the statine residue into peptides that otherwise match sequence preferences of the target enzyme’s sub-sites. Because pepstatin has a low solubility in water, it is often dissolved indimethyl sulfoxide, methanol, or ethanol. Note that many derivatives of pepstatin are available, each displaying a different spectrum of inhibitory effects. Pepstatin B and C are the N-(n-caproyl)- and N-(iso-caproyl)- derivatives, respectively. Note: Above a critical concentration of 0.1 mM in low ionic-strength and neutral buffers, pepstatin often polymerizes into filaments that be several micrometers in length and have characteristic diameters ranging between 6 and 12 nm

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1) Merck Index 14:7147 2) Marciniszyn?et al.?(1976)?Mode of inhibition of acid proteases by pepstatin; J. Biol. Chem.,?251?7088 3) Oda (2012)?New families of carboxy peptidases: serine-carboxyl peptidases and glutamic peptidases; J. Biochem.,?151?13 4) Yoshida?et al. (2006)?Pepstatin A, an aspartic proteinase inhibitor, suppresses RANKL-induced osteoclast differentiation; J. Biochem.,?139?583