title: [Radioligand assay: methods and application. V. Mono-125I-insulin: preparation and immunological and biological characterization].
abstract: A reproducible method for preparation of 125I-monoiodoinsulin with fully biological activity was developed. Monoiodoinsulin has been prepared from a heterogeneous 125I-iodination mixture by anion exchange chromatography on DEAE-Sephadex A-25 without using any gradient elution technique. The specific radioactivity of 125I-monoiodoinsulin was calculated to 14.3 +/- 0.8 TBq/g, i.e. an iodine content of 1.04 +/- 0.06 atoms per molecule of insulin. Monoiodoinsulin was indistinguishable from native insulin with respect to binding to guinea pig anti-insulin serum, and to insulin receptors of isolated rat adipocytes. The biological potency (96.5 +/- 7.5 per cent of the immunoreactive insulin activity) determined by the conversion of [14C1]-D-glucose to 14CO2 in vitro by rat fat cells was not significantly different from that of native insulin.
mesh_terms: D000818:Animals; D002852:Chromatography, Ion Exchange; D007328:Insulin / Q000031:analogs & derivatives* / Q000276:immunology / Q000494:pharmacology; D007457:Iodine Radioisotopes; D007553:Isotope Labeling; D011869:Radioligand Assay; D051381:Rats; D013552:Swine
chemical_list: D007328:Insulin; D007457:Iodine Radioisotopes; C008147:insulin, iodo-
vernacular_title: Radioligandassays: Methodik und Anwendug. V. Mono-125J-Insulin: Präparation, immunologische und biologische Charakterisierung.