PREPARATION OF RADIOLABELED PEPTIDES VIA AN IODINE EXCHANGE-REACTION

Peptides labeled with radioactive I-125 can be detected at the extreme ly low concentrations necessary for receptor binding studies and medic al applications. Traditional methods of iodination often lead to inact ive peptides due to excessive iodination, nonspecific iodination, or o xidative damage to the peptide. In this work these disadvantages are c ircumvented by labeling I-127 containing peptides of a predetermined b iological activity using a radioactive I-125 exchange reaction with (N aI)-I-125. Specific radioactivity up to 9.8 Ci/mmol was reached in a s imple and efficient procedure. (C) 1996 Academic Press, Inc.