title: alpha-Bungarotoxin aggregates on radioiodination with chloramine-T but not with iodogen.
abstract: The presence of polymer(s) of radioiodinated bungarotoxin (Bgt) in preparations iodinated with chloramine-T or with iodogen, was investigated by chromatography on Sephadex-G50. In addition to a monomeric peak (P2), chloramine-T preparations showed a high content of polymeric forms (16-43%) eluting in the void volume (P1), present only to the extent of 1-3% in iodogen preparations. In purified [125I]Bgt prepared by the iodogen method, the content of P1 increased on treatment with chloramine-T, in the absence of radioiodine. The nonspecific binding of [125I]Bgt to DE-81 filter discs was high in the case of chloramine-T preparations and proportional to the content of P1 in each batch. Purified P1 (polymer) but not P2 (monomer) showed a concentration-dependent high degree of binding to DE-81 discs.
mesh_terms: D002038:Bungarotoxins; D055598:Chemical Phenomena; D002621:Chemistry; D002700:Chloramines; D002852:Chromatography, Ion Exchange; D003911:Dextrans; D007457:Iodine Radioisotopes; D011108:Polymers; D014105:Tosyl Compounds; D014508:Urea / Q000031:analogs & derivatives*
chemical_list: D002038:Bungarotoxins; D002700:Chloramines; D003911:Dextrans; D007457:Iodine Radioisotopes; D011108:Polymers; D014105:Tosyl Compounds; C016300:chloramine-T; C012385:1,3,4,6-tetrachloro-3 alpha,6 alpha-diphenylglycoluril; D014508:Urea; C025614:sephadex