HEAT OF SATURATION OF APO AND APO DESIALYLATED HUMAN SERUM TRANSFERRIN AT 298.15 K

To better evaluate the role of sialic acid residues in transferrin sat uration, two different forms of human serum transferrin, namely the ap o and the corresponding apo desialylated forms, were saturated with Fe 3+ and the heats of saturation measured at 298.15 K. In both cases an exothermic reaction was observed, the value being larger for the apo f orm. The presence of sialic acid is believed to facilitate the saturat ion process in human serum transferrin.