Satisfactory radioiodination of rabbit fibrinogen using chloramine-T

A method for radioiodination of fibrinogen using chloramine-T is described. Samples of greater than 90 per cent clottable counts were obtained. Electrophoretic mobility and immunodiffusion showed that the entire radioactivity was present in the fibrinogen band. In vivo studies on the turnover of this labeled product in rabbits showed a half-life of 52.8 to 61.7 hours in two batches of animals. The results compare very well with the reported results obtained from fibrinogen labeled with radioactive iodine by the iodine-monochloride method. The advantages of the new method are indicated.