Optimization of iodination of [I-125]-N-succinimidyl-para-iodobenzoate using Chloramine-T for labeling of proteins

Generally, indirect radioiodination of proteins using N-succinimidyl-iodobe nzoates preserve the biological function of the protein due the mild labeli ng conditions. However, a drawback is that the two-step procedure often giv es a low overall labeling yield. For this reason the production of [I-125] N-Succinimidyl-para-iodobenzoate ([T-125]SPIB), using Chloramine-T as an ox idant, was optimized regarding substrate, oxidant, reaction time, and volum e of the reaction mixture and found to be 86+/-6%. Produced [I-125]SPIB was successfully used for the labeling of monoclonal antibodies.