Separation-Free Enzyme Immunoassay for Haptens
Separation-free (homogeneous) enzyme immunoassays (Emit®) were first developed at the Syva Research Institute in the early 1970s. Their discovery was that binding of an anti-drug antibody to an enzyme labeled with the same drug, modulated (inhibited or activated) catalytic activity. Thus a competitive immunoassay can be developed in which drug in the sample and enzyme-labeled drug compete for antibody. Modulation of enzyme activity is directly related to the analyte concentration in the sample and is monitored without separation of antibody bound and unbound fractions. This principle was later extended to a variety of enzymes and also applied to the measurement of hormones (Ullman et al., 1979) and proteins (Gibbons et al., 1980).
KeywordsTherapeutic Drug Monitoring Dextran Sulfate Enzyme Conjugate Toxicology Assay Oxidize nicotinamIde Adenine Dinucleotide
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- Centofanti, J., A. Monte, D. Grandsaert, B. Chung, M. Ruggieri, R. Schneider, and D. Kabakoff (1981). The EMIT®-stTM drug detection system, J. Clin. Chem. Clin. Biochem. 19: 631.Google Scholar
- Jaklitsch, A.P., R.S. Schneider, R.J. Johannes, J.E. Lavine, and G.L. Rosenberg (1976). Homogeneous enzyme immunoassay for T4 in serum, Clin. Chem. 22: 1185.Google Scholar
- Jaklitsch, A.P., C.B. Gagne, D.S. Kabakoff, D.K. Leung, P. Singh, and W. Protzmann (1980). Measurement of sisomicin concentration in fermentation broths by homogeneous enzyme immmunoassay, Am. Chem. Soc. Meeting MBT 23, Las Vegas, Nev., American Chemical Society.Google Scholar
- Krogsted, D.J., G.G. Granich, P.R. Murray, M.A. Pfaller, and R. Valdes (1982). Heparin interferes with the radioenzymatic and homogeneous enzyme immunoassays for aminoglycosides, Clin. Chem. 28: 1517–1521.Google Scholar
- Rowley, G.L., K.E. Rubenstein, S.T. Weber, and E.F. Ullman (1976). Mechanism by which antibodies inhibit hapten-glucose-6-phosphate dehydrogenase, Am. Chem. Soc, Meeting BIOL 151, Washington, D.C., American Chemical Society.Google Scholar
- Ullman, E.F., R.A. Yoshida, J.I. Blakemore, W. Eimsted, R. Ernst, R. Leute, D.K. Leung, E.T. Maggio, R. Ronald, and B. Sheldon (1979). Mechanism of inhibition of malate dehydrogenase by thyroxine derivatives and reactivation by antibodies. Basis for a homogeneous enzyme immunoassay for thyroxine, Biochim. Biophys. Acta. 567: 66–74.PubMedGoogle Scholar
- Wellington, D. (1981). Mathematical treatments for the analysis of enzyme-immunoassay data. In Enzyme-Immunoassay (E.T. Maggio, ed.) CRC Press, Boca Raton, Fla.Google Scholar