Chinese Name: Z-D-Arg-Gly-Arg-pNA · 2HCl

English Name: Z-D-Arg-Gly-Arg-pNA · 2HCl

Abbreviation: S-2765

CAS Number: 113711-77-6

Molecular Formula: C28H41Cl2N11O7

Molecular Weight: 714.61

Specifications: 25 mg / 100 mg / 1 g (Custom packaging supported)

Purity: ≥98% (HPLC)

Form: Off-white crystalline powder

Product Number: G04010004

Stock: In stock

Color: Yellow

From "colorless peptide" to "yellow signal", the core logic of the chromogenic substrate method:

The full chemical name of S-2765 is Z-D-Arg-Gly-Arg-pNA · 2HCl, which consists of two parts:

• Recognition end (peptide segment): The Z-D-Arg-Gly-Arg sequence is preferentially recognized and cleaved by coagulation Factor Xa.

• Signal end (chromogenic group): When pNA (p-nitroaniline) is attached to the peptide, its absorption signal at 405 nm is weak. Once cleaved and released, free pNA produces strong absorption at 405 nm, resulting in a visually discernible yellow solution.

Chromogenic reaction mechanism:

Factor Xa ---(cleavage)→ Release of pNA ---(405 nm detection)→ Color signal intensity ∝ Enzyme activity

The rate and extent of this reaction directly reflect the activity of Factor Xa in the reaction system. In anti-Xa assays or heparin activity tests, heparin drugs bind to antithrombin (AT) and specifically inhibit Factor Xa activity. Therefore, the remaining unbound Xa activity is inversely proportional to the concentration of heparin – this is the underlying quantification logic of S-2765 in its two major application scenarios.

(I) Determination of coagulation Factor X / FXa activity, mainly used for:

• Congenital Factor X deficiency

• Coagulation disorders caused by liver disease

• DIC (Disseminated Intravascular Coagulation)

• Coagulation factor monitoring

(II) Anti-Xa activity detection of heparin / low molecular weight heparin (LMWH), can quantify:

• Unfractionated heparin

• Low molecular weight heparin (LMWH)

• Certain Factor Xa inhibitor anticoagulants

(III) Determination of antithrombin III (ATIII) activity:

Add excess FXa → ATIII inhibits a portion of FXa → Remaining FXa detected using S-2765

• Less PNA

• Indicates higher ATIII activity

This is one of the important systems for ATIII chromogenic detection.

(IV) Anti-Xa drug monitoring, including:

• Rivaroxaban

• Apixaban

• Edoxaban

(V) Research and Development

1. Study of the coagulation cascade mechanism

S-2765 is a classic tool for studying the dynamics of FX → FXa conversion. Used for: TF/FVIIa extrinsic coagulation pathway, prothrombinase complex, the effect of phospholipid membranes on FXa activation, and coagulation studies on platelet surfaces.

2. Screening of FXa inhibitors

Extensively used in drug development. For example, screening for heparin analogs, polysaccharide anticoagulants, small-molecule FXa inhibitors, and natural product anticoagulant activity. Because it is sensitive, convenient for continuous detection, and has good high-throughput compatibility, it is suitable for high-throughput screening.

3. Study of the hemocompatibility of nanomaterials / biomaterials

For example, blood-contacting materials, catheters, artificial blood vessels, ECM materials, and nanoparticles commonly undergo testing for:

• Whether they promote FX activation

• Whether they enhance FXa generation

S-2765 is a common detection reagent.

4. Protease specificity studies

Although it is biased toward FXa, it is not "absolutely specific"; it is also relatively sensitive to trypsin and certain trypsin-like serine proteases. Therefore, in research it is sometimes used for:

• Trypsin activity determination

• Enzyme kinetics

• Km / kcat studies

✅ High purity, low free pNA background

High-purity peptide synthesis and rigorous purification processes significantly reduce interference from free pNA and degradation impurities, improving accuracy and signal-to-noise ratio in low OD detection.

✅ Inter-batch stability, good methodological consistency

Strict control of key process parameters and quality standards minimizes calibration drift and method variability caused by batch changes, suitable for long-term stable production and clinical system validation.

✅ High selectivity for Factor Xa

The Z-D-Arg-Gly-Arg sequence exhibits good recognition specificity for Factor Xa. The D-Arg design enhances resistance to non-specific enzymatic degradation, reducing the risk of cross-reactivity.

✅ Rapid dissolution, clear solution

The dihydrochloride salt form allows rapid dissolution, reducing the risk of crystallization and turbidity during solution preparation, and minimizing optical detection interference.

✅ Domestic stock, stable supply

Independent production shortens procurement lead times, reduces import dependence and supply risks, while offering cost advantages and delivery stability.