title: Protein precipitation induced by a textile dye. Precipitation of human plasminogen in the presence of Procion Red HE3B.
abstract: It was demonstrated that human purified plasminogen was precipitated in the presence of the textile dye Procion Red HE3B. The amount of precipitated plasminogen was dependent upon the molar ratio between the dye and protein and seemed to be independent of the protein concentration. A certain amount of dye was coprecipitated with the protein; this was shown also to be related to the dye-to-protein molar ratio. The precipitation of plasminogen induced by the dye was shown to have a pH optimum and to involve ionic and hydrophobic interactions. Procedures were devised which enabled the recovery of precipitated plasminogen in a soluble and non-denatured form totally free from dye. However, the precipitation of plasminogen by Procion Red HE3B could not be used as a single-step purification procedure from a heterogeneous starting material like plasma because of coprecipitation of other proteins. Nevertheless it is suggested that frequently there is a chance that a given protein will be precipitated by a given dye and therefore that protein precipitation by dyes could be a useful complementary method for the purification of proteins.
mesh_terms: D015119:Aminocaproic Acid; D004396:Coloring Agents; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010958:Plasminogen / Q000302:isolation & purification*; D011485:Protein Binding; D011506:Proteins / Q000302:isolation & purification*; D013056:Spectrophotometry, Ultraviolet; D014227:Triazines
chemical_list: D004396:Coloring Agents; D011506:Proteins; D014227:Triazines; C020795:procion red HE-3B; D010958:Plasminogen; D015119:Aminocaproic Acid