Avidin radiolabeled

Mamede, M., Saga, T., Kobayashi, H., Ishimori, T., Higashi, T., Sato, N., Brechbiel, M.W., and Konishi, J. (2003) Radiolabeling of avidin with very high specific activity for internal radiation therapy of intra-peritoneally disseminated tumors. Clin. Cancer Res. 9, 3756-3762. 

The determination of the quantity of protein bound to the insoluble carrier sometimes causes difficulties. The methods usually applied are laborious or somewhat inaccurate. Labeling of assayed protein, for instance with C-acet-anhydride, makes it possible to carry out a very fast and exact determination of immobilized protein The determination of bound enzyme C-labeled aldolase after its immobilization on polyacrylamide can serve as an example The concentration measurements of certain proteins are based on their ability to bind certain ligands. Radiolabels such as or H-biotin have been used for the determination of avidin by direct binding or for biotin assay by isotopic dilution Cofactor and fluorescent labeled ligands have been also used for the monitoring of specific protein binding reactions. 

As part of the localization procedure, the antigen-bound primary antibody is detected by a system that permits direct obseiwation of the site of antibody binding. A number of detection systems are available to enhance sensitivity and to visualize primary antibody bound in situ to target antigen. Most of them use either a radiolabeled second antibody and visuahzation by autoradiography, or an enzyme, fluorescent, or electron dense probe coupled to a linking second antibody, protein A, or avidin-biotin amplification system (l.,2). 

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