ELECTROPHORETIC STUDY ON DENATURATION OF HUMAN TRANSFERRIN BY UREA

The aggregation of human transferrin produced by 8 M urea at pH 8.7 was demonstrated by electrophoresis in polyacrylamide agarose gels. Molecules of iron-saturated ferriprotein were protected against denaturation and did not seem to aggregate under these conditions. The presence of sodium dodecyl sulfate in the gel medium, or dilution of the solutions of transferrin, caused the disappearance of all traces of aggregates. Also, a pH below the isoelectric point of the protein, or the addition to the gel of iodoacetamide, eliminated any difference in mobility between proteins unsaturated and those saturated with iron, suggesting an active role for the sulfhydryl groups in the process of aggregation. © 1968.