Enzyme Channelling Immunoassay. A New Homogeneous Enzyme Immunoassay Technique

  • Edwin F. Ullman
  • David J. Litman


Enzyme immunoassays have been widely used for the determination of specific substances in human serum (1). The sample, antibody, and an enzyme-antigen conjugate are combined and the amount of enzyme activity associated with the immune complex is determined. In heterogeneous enzyme immunoassays (ELISA) the free and bound enzyme are physically separated prior to measurement of the enzyme activity (2). In homogeneous enzyme immunoassays the activities of the free and bound enzyme are different and total activity of the solution is determined without a prior separation step (3). The serum concentration of numerous drugs are monitored clinically in this way. The small size of most drugs permits intimate interaction of the antibody and enzyme within the complex and provides mechanisms for modification of enzyme activity. By contrast, it is more difficult to modulate the activity of enzyme conjugates of large antigens such as proteins.


Agarose Bead Order Rate Constant G6PDH Activity Hexokinase Activity Bead Concentration 
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Copyright information

© Plenum Press, New York 1980

Authors and Affiliations

  • Edwin F. Ullman
    • 1
  • David J. Litman
    • 1
  1. 1.Syva Research InstitutePalo AltoUSA

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