Binding affinity of aluminium to human serum transferrin and effects of carbohydrate chain modification as studied by HPLC/high-resolution ICP-MS--speciation of aluminium in human serum.
Aluminium (Al) in the blood is bound to transferrin (Tf), a glycoprotein of about 80kDa that is characterized by its need for a synergistic anion. In this focused review, the binding affinity of Al to Tf is surveyed in the context of our recent studies using on-line high-performance liquid chromatography/high-resolution inductively coupled plasma mass spectrometry (HPLC/HR-ICP-MS). Al in human serum without any in vitro Al-spikes was present in a form bound to the N-lobe site of Tf. The influences of sialic acid in the carbohydrate chain of human serum Tf (hTf) were studied using asialo-hTf, obtained by treatment with sialidase. The binding affinity of Fe was similar between asialo-hTf and native-hTf, while that of Al for asialo-hTf was larger than that for native-hTf, especially in the presence of oxalate, a synergistic anion. The above findings are discussed in relation to diseases in which the serum concentrations of carbohydrate-deficient Tf and oxalate are augmented.
Nagaoka
Megumi Hamano
MH
National Institute of Health Sciences, Kamiyoga 1-18-1, Setagaya, Tokyo 158-8501, Japan. nagaoka@nihs.go.jp
Maitani
Tamio
T
D000535:Aluminum / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D012680:Sensitivity and Specificity; D014168:Transferrin / Q000378:metabolism*
D014168:Transferrin; D000535:Aluminum