GGACK peptide

• Handling and Storage of Synthetic Peptides
• Material Safety Data Sheets (MSDS)

Batch to batch variation of the purity

The GGACK peptide, specifically H-Glu-Gly-Arg-chloromethylketone, is a synthetic tripeptide chloromethylketone inhibitor that targets serine proteases with trypsin-like specificity. Its structure includes a glutamic acid (Glu) residue at the P3 position, glycine (Gly) at P2, and an arginine (Arg) derivative at P1, with a chloromethylketone moiety covalently modifying the active-site histidine residue. This irreversible inhibition mechanism has been instrumental in structural studies, as demonstrated by its use in crystallizing the urokinase-type plasminogen activator (uPA) complex, revealing key interactions within the enzyme's active site.

The peptide's binding mode involves insertion of the arginine side chain into the S1 pocket of uPA, forming a salt bridge with Asp-189, while the chloromethylketone group alkylates His-57, rendering the enzyme inactive. The Glu-Gly-Arg sequence aligns with uPA's substrate preference, and the chloromethylketone modification provides a stable, covalent adduct for X-ray crystallography. This structural insight has facilitated the design of other arginine-mimetic inhibitors targeting serine proteases.

• Sperl S, Jacob U, Arroyo de Prada N, Stürzebecher J, Wilhelm OG, Bode W, Magdolen V, Huber R, Moroder L. (4-aminomethyl)phenylguanidine derivatives as nonpeptidic highly selective inhibitors of human urokinase. Proc Natl Acad Sci U S A. 2000 May 9;97(10):5113-8. doi: 10.1073/pnas.97.10.5113. PMID: 10805774; PMCID: PMC25790.

Trifluoroacetic acid (TFA) is a common counterion from the purification process using High-Performance Liquid Chromatography (HPLC). The presence of TFA can affect the peptide's net weight, appearance, and solubility.

Impact on Net Weight: The TFA salt contributes to the total mass of the product. In most cases, the peptide content constitutes >80% of the total weight, with TFA accounting for the remainder.

Solubility: TFA salts generally enhance the solubility of peptides in aqueous solutions.

In Biological Assays: For most standard in vitro assays, the residual TFA levels do not cause interference. However, for highly sensitive cellular or biochemical studies, please be aware of its presence.