title: Radioiodination of human growth hormone with characterization and minimization of the commonly defined "damaged products".
abstract: The radioiodination and chromatographic purification of human growth hormone (hGH) has been studied in order to better define and control the so-called "preparation damage", which is often a cause of interferences, loss in specific activity and sensitivity, misclassification errors in radioligand assays, and a source of misinterpretation when the tracer is used in receptors or in vivo studies. A series of labelings and false labelings, with and without protein carrier in the buffer used for Sephadex purification, indicate that the "preparation damage" peak is made up of two components: aggregated 125I-hGH and BSA-carried radioactivity. The former can be minimized by the use of recently extracted non-lyophilized hGH, and the latter by enzymatic labeling. Both components can be better resolved, and thus eliminated, when Sephadex G-100 is employed rather than G-75.
mesh_terms: D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D013006:Growth Hormone / Q000032:analysis; D006801:Humans; D007457:Iodine Radioisotopes; D007553:Isotope Labeling / Q000379:methods*; D012711:Serum Albumin, Radio-Iodinated
chemical_list: D007457:Iodine Radioisotopes; D012711:Serum Albumin, Radio-Iodinated; D013006:Growth Hormone