S-2288 (H-D-Ile-Pro-Arg-pNA dihydrochloride)

S-2288 (H-D-Ile-Pro-Arg-pNA dihydrochloride, CAS 96323-41-0) is a chromogenic tripeptide substrate widely used for quantitative measurement of tissue plasminogen activator (t-PA) activity and other arginine-specific serine proteases in fibrinolysis and coagulation research. The substrate features a D-isoleucyl-prolyl-arginyl-p-nitroanilide sequence where t-PA and related proteases cleave the arginyl-pNA bond, releasing yellow p-nitroaniline (ε405 nm = 12,700 M⁻¹cm⁻¹) for continuous kinetic monitoring at 405 nm, enabling precise evaluation of thrombolytic agents, plasma proteolytic activity, and euglobulin lysis time assays. With high sensitivity for t-PA (Km ≈ 1-2 mM) and broad-spectrum reactivity against plasmin, urokinase, plasma kallikrein, and Factor Xa, S-2288 supports diagnostic development, pharmaceutical screening of fibrinolytic drugs, and research into thrombotic disorders using validated microplate and cuvette-based protocols.

Appearance

• White to off-white crystalline powder or lyophilized solid, hygroscopic.
• Highly soluble in water (10-25 mM), stable clear solutions after sonication.

Source

• Solid-phase Fmoc peptide synthesis: H-D-Ile-Pro-Arg-pNA coupling followed by dihydrochloride salt precipitation.
• Commercial diagnostic grade from Chromogenix/DiaPharma (ref. 820852).

Molecular Weight and Structure

• C23H37Cl2N8O5, 577.51 g/mol; free base C23H36N8O5 = 500.60 g/mol.
• H-D-Ile-Pro-Arg-p-nitroanilide·2HCl; cleavable Arg-pNA amide bond.

Sugar Specificity

• None (synthetic peptide chromogen; no carbohydrate components).

Biological Activity

• t-PA Km = 1.0-1.8 mM (pH 7.4, 37°C); linear ΔA405 to 5 µkat/L; ε405 = 12.7 mM⁻¹cm⁻¹.
• Broad-spectrum: plasmin > urokinase > kallikrein > FXa; optimal pH 7.5-8.5.

Purity and Microbial Contamination

• ≥98% HPLC purity; free pNA <0.02%; single peak ≥97.5%.
• Endotoxin-free (<0.1 EU/mg); sterile lyophilized for diagnostic use.

Identity and Quality Control

• RP-HPLC (>98%), LC-MS (m/z 501.3 [M+H]+ free base), AA analysis (1:1:1), specific activity assay.
• Functional test per ISTH/Chromogenix standards; [α]D verified.

Shelf Life and Storage

• 5 years lyophilized at ≤-20°C desiccated; reconstituted stable 1 month -80°C.
• Working solutions stable 24h at RT in Tris buffer; light protected.

Application

• t-PA activity/potency assays; fibrinolytic therapy monitoring.
• Plasma proteolytic activity; euglobulin clot lysis time; plasmin generation.
• Serine protease inhibitor screening; coagulation cascade studies.

Key Characteristics

• High t-PA sensitivity (0.1 IU/mL detection); 96-well automation compatible.
• Broad serine protease reactivity; no fibrinogen interference; validated diagnostic reagent.

Citation Links

• https://www.watson-int.com/h-d-ile-pro-arg-pna-dihydrochloride-cas-96323-41-0/
• https://www.quadratech.co.uk/product/s-2288-for-t-pa-proteolytic-activity-2/
• https://chromogenicsubstrates.com/methods/proteolytic-activity/
• https://www.coachrom.com/en/product-detail/chromogenic-substrates_tpa-serinproteasen_317/p/s-2288tm-820852-1
• https://diapharma.com/wp-content/uploads/2024/01/S820852_Chromogenix_S-2288_Microplate_Method_ML-00-00230REV01.pdf
• https://chemdad.com/index.php?c=article&id=80815
• https://www.endotell.ch/shop/mediafiles/pdf/Chromogenic%20substrates/Chromogenix%20IFU%20&%20Method%20Sheets/Method%20Sheets/MS%20...
• https://www.watson-int.com/category/products-industries/pharmaceutical-chemicals/diagnostic-reagents/
• https://www.caymanchem.com/product/27569/d-pro-phe-arg-pna-hydrochloride
• https://www.bldpharm.com/products/160192-34-7.html