title: Analysis of colloidal gold methods for labelling proteins.
abstract: The relationship between unbound and bound proteins prepared during labelling with colloidal gold (Au) was investigated. For this aim, labelled 125I-bovine serum albumin and 125I-rabbit immunoglobulin were employed. The procedures associated with the washing of the Au labelled proteins (i.e. albumin) had a marked influence on the dissociation of the bound ligand. This was most evident when the concentration of albumin that was used for labelling was too high (0.1 or 1.0 mg/ml Au sol). We suggest that purification of labelled proteins be conducted shortly before use so as to avoid a significant amount of dissociation during the time when the solution is coming to equilibrium.
mesh_terms: D000818:Animals; D002417:Cattle; D003102:Colloids; D006046:Gold; D011485:Protein Binding; D011506:Proteins / Q000032:analysis*; D011817:Rabbits / Q000276:immunology
chemical_list: D003102:Colloids; D011506:Proteins; D006046:Gold