Пепстатин

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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Pepstatin A are natural, statine-containing peptides that acts as inhibitor of aspartic protease enzymes.

Pepstatin A is a naturally occurring chemotactic peptide and inhibitor of aspartic proteases that was initially isolated from culture filtrates of various Actinomycetes species, with the initial name simply of “pepstatin”. This name was later modified to “pepstatin A” to distinguish the original pepstatin from later derivatives. Pepstatin A notably contains the unusual amino acid 4-amino-hydroxy-6-methylheptanoic acid (AHMHA), which is known also as statine. The amino acid sequence of pepstatin A is N-Isovaleryl-L-Valyl-L-Valyl-AHMHA-L-Alanyl-AHMHA.

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