Proteins radio-iodinated

Fourth, they are difficult to measure in body fluids. There are very precise ways of measuring very small quantities, in plasma or urine, of almost all conventional medicines and this has made it possible to make the kinetic measurements we have been considering earlier. Some of the techniques for the big protein medicines are not as reliable. For example, one way of tracing a big molecule s progress through the body is to label it with a radioactive tracer. Biopharmaceuticals can be labelled with, for example, radio-iodine (Iodine-125) which can be counted in samples of plasma or urine. However as proteins are similar or identical to normal proteins they can be metabolised and the label can become part of a metabolite or another breakdown product. Counting the iodine radioactivity in this case will not be measuring the parent molecule alone. 

We thank the Royal Society (UK) for a postdoctoral fellowship (GRM) and the University of Otago for a research grant. We are grateful to Michael Crawford for production of biological artwork, Jesse Gale for technical advice on radio-iodination of proteins, Drs Sarah L. Heath and David S. Larsen for helpful discussions, Drs Sally P.A. McCormick, Stephen Faulkner, and Wolfgang Mohr for critically reading this manuscript, Tanya K. Ronson for her help with the references and Dr Katie Heslop for additional help with manuscript production. 

Studies using radio-iodinated proteins in the TIRF apparatus permit a direct measurement of the amount adsorbed, thus allowing one to deduce if the quantum yield is also changed on adsorption84). 

NIS iodinates uracil and pyrimidine derivatives in CF3CO2H-(CF3CO)2O740.Proteins are iodinated for radio immunoassay under similar conditions741. 

When radioactive iodine is to be used, it should be purchased as Na I, free of carrier, or reducing agents. Picogram quantities of radio-iodine labelled proteins can be detected readily. 

We thank the Royal Society (UK) for a postdoctoral fellowship (GEM) and the University of Otago for a research grant. We are grateful to Michael Crawford for production of biological artwork, Jesse Gale for technical advice on radio-iodination of proteins,... 

The first series of metallo-carbonyl protein labeling reagents was designed from the popular Bolton-Hunter radio-iodination reagent 48 intended for antibody radiolabeling [85]. 

Franek, M. and Hruska, K. J. Simple Separation of Iodide from Radio-iodinated Proteins by Ion-Exchange Chromatography-Centrifugation. J. Chromatog. No. 2, 471 (1974). 30 18368... 

---