HD-Phe-Pip-Arg-pNA (S-2238) acetate is a chromogenic substrate formed after the N-terminal portion of the fibrinogen alpha chain, the natural substrate of thrombin. HD-Phe-Pip-Arg-pNA acetate is specific for thrombin and is used to measure antithrombin heparin cofactor (AT-III). AT-III analysis using HD-Phe-Pip-Arg-pNA acetate is sensitive, accurate, and easy to perform.

Physicochemical Properties

Molecular Formula	C29H40N8O7
Molecular Weight	612.68
Exact Mass	552.281
CAS #	115388-96-0
Related CAS #	H-D-Phe-Pip-Arg-pNA hydrochloride;160192-34-7;H-D-Phe-Pip-Arg-pNA;64815-81-2;H-D-Phe-Pip-Arg-pNA dihydrochloride;62354-65-8
PubChem CID	13020984
Appearance	White to yellow solid powder
LogP	4.048
Hydrogen Bond Donor Count	5
Hydrogen Bond Acceptor Count	7
Rotatable Bond Count	11
Heavy Atom Count	40
Complexity	892
Defined Atom Stereocenter Count	0
SMILES	NC(=N)NCCC[C@@H](C(=O)NC1=CC=C(N(=O)[O-])C=C1)NC(=O)C2N(CCCC2)C(=O)[C@H](N)CC3=CC=CC=C3
InChi Key	YDMBNDUHUNWWRP-AXWGZAFASA-N
InChi Code	InChI=1S/C27H36N8O5/c28-21(17-18-7-2-1-3-8-18)26(38)34-16-5-4-10-23(34)25(37)33-22(9-6-15-31-27(29)30)24(36)32-19-11-13-20(14-12-19)35(39)40/h1-3,7-8,11-14,21-23H,4-6,9-10,15-17,28H2,(H,32,36)(H,33,37)(H4,29,30,31)/t21-,22+,23?/m1/s1
Chemical Name	1-[(2R)-2-amino-3-phenylpropanoyl]-N-[(2S)-5-(diaminomethylideneamino)-1-(4-nitroanilino)-1-oxopentan-2-yl]piperidine-2-carboxamide
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

References

[1]. Goodnight SH Jr, et al. Measurement of antithrombin III in normal and pathologic states using chromogenic substrate S-2238. Comparison with immunoelectrophoretic and factor Xa inhibition assays. Am J Clin Pathol. 1980;73(5):639-647. [2]. Voorthuizen H, Kluft C. Improved assay conditions for automated antithrombin III determinations with the chromogenic substrate S-2238. Thromb Haemost. 1984;52(3):350-353.

Solubility Data

Solubility (In Vitro)

DMSO: 100 mg/mL (163.22 mM) H2O: < 0.1 mg/mL

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (4.08 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 2.5 mg/mL (4.08 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	1.6322 mL	8.1609 mL	16.3217 mL
	5 mM	0.3264 mL	1.6322 mL	3.2643 mL
	10 mM	0.1632 mL	0.8161 mL	1.6322 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.