title: Mild radioiodination of insulin with dichloramine-T.
abstract: Iodination of insulin using N-dichloro-p-toluene sulphonamide(dichloramine-T) has been standardised. Dichloramine-T, a water insoluble derivative of chloramine-T showed excellent properties as an iodination reagent, for the preparation of radiolabeled insulin for use in radioimmunoassay. Iodination using dichloramine-T could be done at as low as 0.5-2 micrograms of the reagent, and at this concentration the molar ratio worked out to 1:3 to 1:12 (protein:dichloramine-T). Iodination yields of greater than 90% were obtained at pH 5-7. Evaluation of the iodinated tracer for suitability in radioimmunoassay was carried out by estimating radiochemical purity, immunological purity, non specific binding and stability on storage.
mesh_terms: D007328:Insulin / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D007457:Iodine Radioisotopes; D007553:Isotope Labeling / Q000379:methods; D007700:Kinetics; D011863:Radioimmunoassay; D013449:Sulfonamides; D000096926:Benzenesulfonamides
chemical_list: D007328:Insulin; D007457:Iodine Radioisotopes; D013449:Sulfonamides; C008147:insulin, iodo-; C051638:dichloramine-T; D000096926:Benzenesulfonamides