DISCONTINUED - REPLACEMENT: Chromogenix S-2251 (S820332) or S-2403 (S822254)

For research use only.

S-2390 is a chromogenic substrate designed for the determination of t-PA and t-PA-inhibitor in plasma via plasminogen activation. The substrate has hitherto only been used in methods where plasminogen is activated by t-PA (tissue plasminogen activator) in the presence of fibrin monomer or equivalent stimulators. It has been used for the assay of t-PA, t-PA inhibitor and fibrin monomer in plasma.

Reagent -- Composition, Packaging, Storage and Stability

Each vial contains chromogenic substrate S-2390. Stability: Substrate: stable until expiry date if stored at 2-8°C. Avoid exposure to light. The substrate is hygroscopic and should be stored dry. Solution: 2 mmol/l in H2O is stable for more than two months at 2 to 8°C.

Chemistry

Chemical name: H-D-Valyl-L-Phenylalanyl-LLysine-p-nitroanilinedihydrochloride

Formula: H-D-Val-Phe-Lys-pNA · HCl

Mol. wt: 585.6

e316 nm: 1.27 · 104 mol-1 · L · cm-1

Solubility: > 40 mmol/L in H2O

Suitable stock solution: 1-2 mmol/l in H20

Principle

	Enzyme
H-D-Val-Phe-Lys-pNA		H-D-Val-Phe-Lys-OH+pNA

The method for the determination of activity is based on the difference in absorbance (optical density) between the pNA formed and the original substrate. The rate of pNA formation, i.e. the increase in absorbance per second at 405 nm, is proportional to the enzymatic activity and is conveniently determined with a photometer.

Kinetic Data

Plasmin: Km = 3 · 10-5 mol/l and kcat = 20 sec-1. Determined in 0.05 mmol/l Tris

pH 7.4, I 0.15 at 37°C.