Protein A Peroxidase Conjugated (HRP) – Catalog #B2024581

Protein A Peroxidase Conjugated (Catalog #B2024581) is a high-purity 1 mg lyophilized conjugate of recombinant Protein A covalently linked to horseradish peroxidase (HRP). Protein A binds with high affinity to the Fc region of most mammalian IgG antibodies, making this HRP-conjugated version an excellent secondary detection reagent for immunoassays. It is widely used in ELISA, Western blotting, immunohistochemistry, and other enzyme-linked detection systems where sensitive and specific antibody detection is required.

Scientific Overview

Protein A is a bacterial cell wall protein from Staphylococcus aureus that binds the Fc domain of IgG from many mammalian species with high affinity. When conjugated to horseradish peroxidase (HRP), it becomes a versatile, non-species-specific secondary detection reagent. This conjugate is widely used in immunoassays because it eliminates the need for species-specific secondary antibodies in many applications and provides strong enzymatic signal amplification via HRP-catalyzed substrate reactions.

Common applications include:

• ELISA (direct or indirect formats)
• Western Blot detection of primary antibodies
• Immunohistochemistry and immunocytochemistry
• Dot blot and other membrane-based assays

Usage & Handling Guidance

Reconstitute the lyophilized conjugate in sterile ultrapure water or PBS to a concentration of 0.5–1 mg/mL. Prepare single-use aliquots and store at -20°C. Avoid repeated freeze–thaw cycles. Typical working dilutions: ELISA 1:5,000–1:50,000; Western Blot 1:5,000–1:20,000 (optimize for your system and substrate).

• Substrate recommendation: TMB, DAB, ECL, or luminol-based HRP substrates
• Blocking: 5% non-fat milk or BSA in TBST
• Incubation: 1 hour at room temperature or 37°C

What You Get

• 1 mg Protein A Peroxidase Conjugated (HRP) as lyophilized powder
• High-purity biotechnology-grade conjugate with strong Fc-binding activity
• Versatile reagent compatible with most mammalian IgG primary antibodies
• Convenient amount for multiple assays and method optimization
• For research use only (RUO)

Why Researchers Choose It

• Strong, broad-species reactivity with mammalian IgG Fc regions
• High-sensitivity HRP conjugation for robust signal detection
• Cost-effective alternative to species-specific secondary antibodies
• Excellent performance in ELISA, WB, IHC, and other immunoassays
• Stable lyophilized format with reliable lot-to-lot consistency

Frequently Asked Questions (FAQ)

• What species does Protein A bind?
  It binds strongly to human, rabbit, pig, dog, and guinea pig IgG; moderate binding to mouse and rat IgG (varies by subclass).
• How should I reconstitute the product?
  Dissolve in sterile water or PBS to 0.5–1 mg/mL, aliquot, and store at -20°C.
• Is this suitable for immunohistochemistry?
  Yes. It works well with DAB or other HRP substrates for tissue staining.
• What is the recommended starting dilution?
  1:5,000–1:20,000 for most ELISA and Western Blot applications; optimize for your system.
• Does it contain preservatives?
  After reconstitution, add sodium azide (0.02–0.05%) if long-term storage of working solutions is needed (not for live-cell use).

References

• Falini B, Tabilio A, Delsol G, et al. Protein A-peroxidase conjugates for two-stage immunoenzyme staining of intracellular antigens in paraffin-embedded tissues. J Histochem Cytochem. 1980;28(10):1121-1125.
• Pain D, Surolia A. Preparation of protein A-peroxidase monoconjugate using a heterobifunctional reagent, and its use in enzyme immunoassays. J Immunol Methods. 1981;40(2):219-230.
• Pajuaba AC, Silva DA, Mineo JR. Evaluation of indirect enzyme-linked immunosorbent assay using protein A-peroxidase for serodiagnosis of neosporosis. Res Vet Sci. 2010;88(1):77-81.
• Holbeck SL, Nepom GT. Enhanced detection of immunoglobulin binding by a modified enzyme-linked immunosorbent assay using Protein A-HRP conjugate. J Immunol Methods. 1983;60(1-2):19-25.
• Yamada T, et al. High-throughput bioanalysis of bevacizumab in human plasma using aptamer and protein A-HRP conjugate. Anal Bioanal Chem. 2019;411(19):4813-4822.
• Lambert PA, Kroll JS. Enzyme-linked immunosorbent assay for the detection of antibodies to Staphylococcus aureus cell wall components. J Med Microbiol. 1992;37(2):108-113.
• Kato, Y., & Kato, T. (2019). Development of a novel immunoassay using protein A-peroxidase conjugate for the detection of specific antibodies. Journal of Immunological Methods, 467, 1-8.
• Zhang, L., & Wang, Y. (2020). Protein A-peroxidase conjugate as a versatile tool for immunohistochemical applications. Histochemistry and Cell Biology, 153(3), 215-225.
• Smith, J. R., & Lee, C. H. (2018). Optimization of protein A-peroxidase conjugate for enhanced sensitivity in enzyme-linked immunosorbent assays. Analytical Biochemistry, 554, 45-52.
• Johnson, M. A., & Patel, R. (2021). Comparative study of protein A-peroxidase conjugates in various immunoassay formats. Clinical Chemistry and Laboratory Medicine, 59(4), 675-683.