PeptideSciences The Direct Peptide Reactivity Assay (DPRA) is a crucial in chemico method used to assess the potential of chemicals to cause skin sensitization.Test No. 442C: In Chemico Skin Sensitisation This assay is a key component of regulatory guidelines, specifically recognized as an OECD test guideline method (OECD 442C).2019年11月27日—Skin sensitization potency can be investigated by measuring the kinetic rates of cysteine peptide depletion using thekinetic DPRA assay. Its primary function is to address the first molecular key event of the adverse outcome pathway (AOP) of skin sensitization, which involves the reaction of a chemical with skin proteins. By measuring this reactivity, the DPRA helps to identify dermal sensitizers early in the development process, contributing to the development of safer chemical ingredients, particularly for use in cosmetics作者：JDC Hemming·2019·被引用次数：15—The DPRAexamines the reactivity of a test compound to two model peptides(containing either cysteine or lysine) and consequently is able to ....
The DPRA operates by quantifying the reactivity of a test chemical with specific model peptides. These peptides are designed to contain either cysteine or lysine residues, representing the nucleophilic amino acid residues found in proteins that are susceptible to reaction with electrophilic chemicals. The fundamental principle is to measure the depletion of these peptides after incubation with the test substance. A significant depletion indicates that the chemical has reacted with the peptide, suggesting a potential for it to react with skin proteins and thus cause sensitization.
The assay typically involves incubating a test chemical with two types of synthetic peptides: one containing cysteine and another containing lysineCan the Direct Peptide Reactivity Assay Be Used for the .... After a defined incubation period, usually 24 hours, the remaining concentration of each peptide is quantified.Full article: Peptide reactivity assays for skin sensitisation This quantification allows for the calculation of peptide depletion, which is then used to assess the chemical's sensitizing potentialPeptide reactivity assays for skin sensitisation. The Direct Peptide Reactivity Assay (DPRA), often performed under Good Laboratory Practice (GLP) conditions, provides valuable data for regulatory submissions and risk assessments.
The DPRA is designed to mimic the initial molecular event in the skin sensitization process: haptenation. This is where a reactive chemical (hapten) covalently binds to a protein, forming an immunogenic complex. The assay directly measures this binding of test chemicals to model synthetic peptides.2025年11月10日—OurGLP Direct Peptide Reactivity Assay (DPRA) enables our clients to determine if their chemicals present these challenges quickly and generate ...
* Peptide Selection: The use of peptides containing cysteine and lysine is strategic. Cysteine residues, with their thiol groups, are highly nucleophilic and readily react with electrophilic chemicals. Lysine residues, with their amino groups, also act as nucleophiles. By testing against both, the assay captures a broader range of potential chemical reactions.
* Quantification: The depletion of peptides is typically measured using spectrophotometric methods or other analytical techniques that can accurately determine the remaining peptide concentrationThe DPRA isone of three test methods(KeratinoSens TM and h-CLAT) for the assessment of skin sensitisation potential.. A vehicle control is used to account for any non-specific loss of peptide.Building on the original DPRA (OECD TG 442C),this test assesses multiple substance concentrations and time pointsto provide quantitative reaction data.
* In Chemico Approach: It's important to note that the DPRA is an in chemico method. This means it studies chemical reactions in a controlled laboratory setting, outside of a living organism. This approach offers advantages in terms of specificity and mechanistic understanding compared to some in vivo methodsDirect Peptide Reactivity Assay (DPRA, OECD 442C).
The Direct Peptide Reactivity Assay (DPRA), also known by its OECD guideline number OECD 442C, is a significant advancement in the assessment of skin sensitization potential, offering a non-animal alternative.Thedirect peptide reactivity assay(DPRA) is used to contribute to the assessment of the skin sensitisation potential of chemicals. It is often used in conjunction with other in vitro and in chemico methods, such as the KeratinoSens™ assay and the human Cell Line Activation Test (h-CLAT), to form a comprehensive testing strategy for skin sensitizationCan the Direct Peptide Reactivity Assay Be Used for the ....
* Regulatory Acceptance: As an OECD test guideline, the DPRA is widely accepted by regulatory authorities for chemical safety assessments.
* Screening Tool: It serves as an effective screening tool for identifying chemicals that are likely to be skin sensitizers, allowing for early elimination of problematic substances from product formulations.
* Mechanistic Insight: By focusing on the initial molecular event, the DPRA provides valuable mechanistic insight into the process of skin sensitization.
* Cosmetic Ingredients: The assay is particularly relevant for assessing the safety of chemical ingredients used in cosmetics and other consumer productsApplication of the direct peptide reactivity assay (DPRA) to ....
While the standard DPRA provides valuable information, advancements have led to variations such as the Kinetic Direct Peptide Reactivity Assay (kDPRA). The kDPRA builds upon the original method by assessing multiple substance concentrations and time pointsDirect Peptide Reactivity Assay (DPRA). This allows for the determination of quantitative reaction data, including reaction rates, which can provide a more nuanced understanding of a chemical's sensitization potency. By measuring the kinetic rates of peptide depletion, the kDPRA offers a more detailed picture of the chemical's reactivity profile.
In conclusion, the Direct Peptide Reactivity Assay (DPRA) is a vital tool in modern chemical safety assessmentThe OECD 442C in chemico direct peptide reactivity assay (DPRA)examines the first molecular key event of haptenationwithin the adverse outcome pathway .... Its ability to address the first molecular key event of the adverse outcome pathway of skin sensitization by measuring the reactivity of chemicals with model peptides containing lysine or cysteine residues makes it an indispensable method for identifying potential dermal sensitizers and contributing to the development of safer chemical products.The Direct Peptide Reactivity Assay: Selectivity of Chemical ...
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