Radiolabeling of the biologically active peptide 163-171 of human interleukin-1 beta.

N-succinimidyl[2,3-3H]propionate was used for the radiolabeling of the biologically active peptide fragment 163-171 of human interleukin-1 beta (VQGEESNDK). Suitable reaction conditions were studied to obtain useful labeling of the molecule. A mixture of mono- (70%) and bi- (30%) propionyl derivatives was obtained with a total 3H specific activity of 87 Ci/mmol of peptide. The conditions for an efficient chromatographic separation of labeled peptide from unreacted reagents and by-products were established. The labeled peptide maintained the same biological activity as that of the corresponding unlabeled molecule, indicating that the labeling procedure did not alter the biological characteristics of the peptide. This thus allows the use of the radiolabeled peptide for receptor binding studies.