A unique kit for the detection of Dibromo-tyrosine

Dibromo-tyrosine is produced by the oxidative bromination of tyrosine residues. This reaction occurs via eosinophil peroxidase (EPO), an enzyme released by activated eosinophils. Upon activation of eosinophils, a respiratory burst occurs releasing elevated levels of O2 and H202. In the oxidation of tyrosine, EPO utilises H202 to catalyse the peroxidation of physiological levels of bromine found within plasma to generate the brominating reagent hypobromous acid (HOBr) (Ref: 1-5)

Figure 1. Bromination of tyrosine (Ref: 8)

Eosinophils play an immunomodulatory role through their recruitment to host sites of parasitic invasion. EPO levels also contribute to diseases such as asthma, cancers and allergic disorders where cellular activation is found to occur at pathological sites (Ref: 6-10)

Brominated products such as 3,5-dibromo-tyrosine serve as biological markers for in vivo eosinophil-mediated tissue damage which allows for understanding the overall roll oxidative stress has on pathways implicated in diseased states within organisms (Ref: 4) .


About This Assay

This unique kit is part of the StressMarq range. It is a is a competitive ELISA assay that can be used for the quantification of 3,5-dibromo-tyrosine in urine, plasma, and other sample matrices. The assay utilises a dibromo-tyrosine-coated plate and an biotin-conjugated antibody for detection which provides an assay range of 0.078 - 5 μg/mL, with a sensitivity of 0.04 μg/mL. Additional kit highlights are quick incubation times, stable reagents, and an easy to use protocol.

It is important to note that the dibromo-tyrosine antibody used in this assay recognises both free dibromo-tyrosine and brominated residues within a protein. Since complex samples such as plasma, are comprised of mixtures of protein fragments and free 3,5-dibromo-tyrosine, concentrations of 3,5-dibromo-tyrosine reported by ELISA methodology may not coincide with literature values where the free residue is typically measured. This should be kept in mind when analysing and interpreting experimental results.



Assay Overview

Figure 2. Schematic of the dibromo-tyrosine competitive ELISA

Further details for this kit are available here:
Dibromo-tyrosine ELISA Kit Details and Pricing

References:
1. MacPherson, J.C., Comhair, S. A. A., Erzurum, S.C., et al. Eosinophils are a major source of nitric oxide-derived oxidants in severe asthma: characterization of pathways available to eosinophils for generating reactive nitrogen species. J. Immun. 166, 5763-577 (2001).
2. Mayeno, A. N., Curran, A. J., Roberts, R. L., et al. Eosinophils Preferentially Use Bromide to Generate Halogenating Agents. J. Biol. Chem. 264, 5660-5668 (1989).
3. Babior, B. M. Oxygen-dependent microbial killing by phagocytes. N. Engl. J. Med. 298, 659-668 (1978).
4. Wu W., Chen, Y., d’Avignon, A. et al. 3-Bromotyrosine and 3,5-dibromotyrosine are major products of protein oxidation by eosinophil peroxidase: potential markers for eosinophil-dependent tissue injury in vivo. Biochem. 38, 3538-3548 (1999)
5. Kambayashi, Y., Ogino, K., Takemoto, K. et al. Preparation and characterization of a polyclonal antibody against brominated protein. J. Clin. Biochem. Nutr. 44, 95-103 2009
6. Wang J., Slungaard A. Role of eosinophil peroxidase in host defense and disease pathology. Arch. Biochem. Biophys. 445, 256–260 (2006).
7. Kazura, J. W., Fanning, M. M., Blumer, J. L. Mahmoud, A. A. Role of cellgenerated hydrogen peroxide in granulocyte-mediated killing of schistosomula of Schistosoma mansoni in vitro. J. Clin. Invest. 67, 93 (1981).
8. Klebanoff, S. J., Locksley, R. M., Jong, E. C., Rosen, H. Oxidative response of phagocytes to parasite invasion. CIBA Found. Symp. 99: 92 (1983)
9. Gleich, G. J., Ottesen, E. A., Leiferman, K. M., Ackerman, S. J. Eosinophils and human disease. Int. Arc. Allergy Appl. Immunol. 88: 59 (1989).
10. Wardlaw, A. J., Eosinophils in the 1990s: new perspectives on their role in health and disease. Postgrad. Med. J. 70: 536 (1994).