Binding of aluminum to human serum transferrin, human serum albumin and rat serum proteins.

Abstract:  Human serum transferrin (HSTF), human serum albumin (HSA) and rat serum were compared for their interaction with AlCl3, in a Tris-HCl buffer solutions (pH 7.4). The AlCl3 was tested in series of concentrations in the range of 50 microM up to 500 microM. HSTF, HSA and their 1:1 mixture and rat serum were incubated at 37 degrees C with series of AlCl3 concentrations. The protein profile of the incubated solutions were compared to control using SDS-PAGE and FPLC tests. The results indicated that HSTF was more specifically responsive to AlCl3 showing a characteristic increase in its UV absorption, peak and area dimensions. Simultaneously, HSA was less affected, but it showed a significant shift with an increase in molecular weight accompanied with a change in its profile. The respective bands of transferrin and albumin in rat serum behaved similarly. The SDS-PAGE and FPLC data coincided and confirmed the preferential affinity of HSTF to bind with Al3+. These results support the suggestion of using HSTF for monitoring levels of Al3+ in human blood samples of exposed population. The importance of further developing such a biomarker is the increased demand for early detection of the hazardous levels of Al3+ in relation to its long term neurotoxic adverse effects.