A RAPID AND ECONOMICAL METHOD OF PREPARING RADIOIODINATED CYCLIC-NUCLEOTIDE DERIVATIVES FOR USE IN RADIOIMMUNOASSAYS

2 ’ -O-succinyladenosine 3‘ :5’-cyclic monophosphate tyrosyl methyl ester (ScAMP-TME) and 2’-0-succinylguanosi.ne 3‘:5’-cyclic monophosphate tyrosyl methyl ester 125(ScGMP-TME) were radioiodinated using chloramine T and Na I. The 125 resulting radiolngled cyclic nucleotide derivatives, ScAMP- I-TME and ScGMP- I-TME, were subsequently purified by reverse-phase chromatography on Sep-Pak Cl8 cartridges (Waters Associates, Milford, MA) and tested as tracers in sensitive radioimmunoassays for caMP 125 and cGMP, respectively. Purified ScAMP- I-TME and ScGMP- I-TME functioned in the respective radioimmunoassays for up to 12 weeks when suspended in a 1:1 (v:v) mixture of n-propanol and 20 mM sodium acetate, pH 6.0. Thus, this purification method enables rapid and economical preparation of tracers for cyclic nucleotide radioimmunoassays. Furthermore, our findings suggest that reverse-phase chromatography may be applicable to the purification of other small polar molecules to which tyrosyl groups have been added for the purpose of radioiodination. (KEY WORDS: cyclic nucleotides, radioimmunoassay, reverse-phase chromatography, radioiodination). © 1990, Taylor & Francis Group, LLC. All rights reserved.