Radioiododestannylation. Convenient synthesis of a stable penicillin derivative for rapid penicillin binding protein (PBP) assay

Radioiodination of p ‐(trimethylstannyl)penicillin V with [ 125 I]Na using a modification of the chloramine‐T method is simple, high yielding, and site‐specific. The structure and penicillin binding protein (PBP) affinity of p ‐[ 125 l]‐penicillin V (IPV) are similar to penicillin G and the product can be used directly without purification in the PBP assay. Because of the high degree of stability toward autoradiolysis and equivalent PBP binding affinity, IPV can be used in place of [ 3 H]‐penicillin G or [ 14 C]‐penicillin G for these experiments.