S-2238 (chemical name: H-D-Phe-Pip-Arg-pNA) is one of the classic chromogenic substrates for thrombin. In the rapidly changing IVD raw material market, its lasting vitality stems from its ingenious underlying molecular design and extensive clinical and methodological validation.

Specifically, its "classic" status is reflected in the following three dimensions:

1. Ingenious mechanism: one reaction, two roles

S-2238 is essentially a chromogenic substrate used to monitor thrombin activity. Its structure simultaneously contains: a peptide sequence responsible for enzyme recognition and a pNA chromogenic group for generating the detection signal.

• Peptide moiety (H-D-Phe-Pip-Arg): This sequence is highly compatible with the catalytic active center of thrombin. It is efficiently and specifically recognized and cleaved by thrombin. This "specific recognition" characteristic allows it to maintain extremely high anti-interference ability even in complex plasma samples;

• Reporter group (pNA): After the peptide is cleaved, p-nitroaniline (pNA) is released, resulting in a significant increase in absorbance at 405 nm. The more pNA released in the system, the stronger the 405 nm absorbance signal, and the higher the corresponding thrombin activity. This makes enzyme activity changes visible, precise, and measurable;

2. Long-term validation: stable and reliable technical support

S-2238's classic status in the industry stems not only from its excellent enzymology design but also from years of validation in actual detection scenarios.

S-2238 substrate was applied early in clinical coagulation chromogenic assays and has been widely used in detection systems such as ATIII, anti-IIa, and thrombin activity analysis for decades. Numerous research papers, automated detection schemes, and commercial kits in the industry have built their detection methods based on this substrate.

The rich application data and technical accumulation provide strong technical support for reagent formulation replication, process optimization, and result traceability.

3. Flexible process: same sequence, multiple salt forms

All S-2238 substrates have identical peptide sequences, differing only in the counterion (hydrochloride/acetate) and its molarity. This does not change the enzymatic specificity of the substrate but profoundly affects key physicochemical indicators in kit development:

• Dissolution rate and solubility limit in aqueous solution

• Cake morphology and reconstitution behavior after lyophilization

• Potential perturbation of ionic strength and pH of the reaction system

• Long-term storage stability of liquid reagents

Chinese Name: Thrombin Chromogenic Substrate S-2238 Dihydrochloride

English Name: H-D-Phe-Pip-Arg-pNA ∙ 2HCl

Abbreviation: S-2238

CAS Number: 62354-65-8

Molecular Formula: C27H38Cl2N8O5

Molecular Weight: 625.55

Specifications: 25 mg / 100 mg / 500 mg (Custom packaging supported)

Form: Off-white crystalline powder

Product Number: G04010024

Stock: In stock

Color Signal: Yellow absorption at 405 nm

Chinese Name: Thrombin Chromogenic Substrate S-2238 Diacetate

English Name: H-D-Phe-Pip-Arg-pNA ∙ 2AcOH

Abbreviation: S-2238

CAS Number: 386253-60-7

Molecular Formula: C31H44N8O9

Molecular Weight: 672.74

Specifications: 25 mg / 100 mg / 500 mg (Custom packaging supported)

Form: Off-white crystalline powder

Product Number: G04010025

Stock: In stock

Color Signal: Yellow absorption at 405 nm

1. Antithrombin III (ATIII) chromogenic assay

S-2238 is one of the classic chromogenic substrates for thrombin and can be used in ATIII activity detection systems based on the "residual thrombin method". After ATIII reacts with thrombin, the remaining thrombin's ability to cleave S-2238 is measured to quantify ATIII activity. Suitable for:

• ATIII chromogenic assay development;

• Method establishment on automated coagulation platforms;

• Continuous kinetic detection systems;

• Clinical coagulation function research;

2. Heparin anti-IIa chromogenic detection system

Used in some anti-IIa heparin assays to monitor the inhibitory effect of heparin on thrombin activity. Helps in:

• Heparin activity analysis;

• Anti-IIa methodology development;

• Establishment of automated coagulation systems;

• Long-term stability validation;

✅ High purity control, helps reduce 405 nm background interference

The S-2238 series uses high-purity peptide synthesis and purification processes, which can reduce the impact of free pNA and some degradation impurities on 405 nm background absorption. In continuous kinetic detection systems such as ATIII and anti-IIa, this helps improve data stability in low enzyme activity ranges and reduces the interference of blank well background drift on the standard curve.

✅ Sequence design tailored to thrombin recognition characteristics

Based on thrombin's highly selective cleavage preference for the D-Phe-Pip-Arg sequence, the S-2238 series adopts this classic sequence design, offering high recognition selectivity for thrombin, thereby reducing potential interference from other serine proteases in the detection system. It can be used for anti-IIa methodology development and continuous kinetic analysis of thrombin, making it more suitable for clinical coagulation monitoring and cleavage mechanism studies.

✅ Excellent batch-to-batch consistency, ensuring reagent stability

Each batch of substrate undergoes rigorous kinetic curve determination and quality control. Excellent batch-to-batch consistency ensures the long-term stability of the kit's calibration curve, effectively reducing the risk of quality control fluctuations caused by substrate batch changes.

✅ Multiple salt forms adaptable to different development stages

To meet the different needs of research development, automated platforms, and IVD process systems, Hepattack Bioscience & Technology offers various salt forms including free base, HCl salt, and AcOH salt. In some systems, this can help improve solution stability, reduce the risk of precipitation at low temperatures, and enhance method consistency under long-term storage conditions.

✅ High cost-effectiveness, domestic in-stock supply

Common specifications (25 mg, 100 mg, 500 mg) are available for immediate shipment. Relying on in-house R&D and production, we eliminate additional cost factors such as cross-border transportation, agent distribution, and tariffs, offering outstanding price advantages and helping enterprises effectively control raw material procurement costs.