Purification and hetrogeneity of human transferrin by polyacrylamide gel electrophoresis

Abstract

Human transferrin was purified from serum using polyacrylamide gel disc electrophoresis. The purified transferrin appeared to be free from other protein, as judged by electrophoresis on polyacrylamide gel and by immunoelectrophoresis. The purified human transferrin was resolved into a faster moving band (TF) and a slower moving band (TS) by 5.25% polyacrylamide gel electrophoresis. Analysis of the purified human transferrin by isoelectric focusing column separated this iron-transport protein into three components with isoelectric points of 5.61, 5.18 and 4.53. Electrophoresis on 5.25% polyacrylamide gel was carried out on each fraction from the column. Fractions pI 5.61 and pI 5.18 both moved with the same mobility as the slower electrophoretic component (TS). Fraction pI 4.53 moved with the same mobility as the faster electrophoretic component (TF). After recovery from the isoelectric column pI 5.18 transferrin was found to contain 0.90, 1.57 atoms of iron/mol of protein. The pI 4.53 transferrin had less than 0.05 atoms of iron/mol of protein. The pI 5.61 transferrin contained 0.51, 0.65 atoms of iron/mol of protein.