title: Direct spectrophotometric determination of the two site binding of aluminum to transferrin.
abstract: Difference UV spectrophotometry is used to determine the conditional binding constants for aluminum to human transferrin in the presence of HCO3- of initial concentration 18 mM according to a two site model. The values obtained at 37 degrees C and pH 7.4 are: K1 = 3.0 (+/- 0.8) X 10(15) M-2, K2 = 2.9 (+/- 0.7) X 10(15) M-2 for the reactions: Tr + Al3+ + HCO3- = Tr-Al-HCO3 and Tr-Al-HCO3 + Al3+ + HCO3- = Tr-Al2-(HCO3)2 respectively. Possible consequences arising for the transport of aluminum in human serum are discussed.
mesh_terms: D000535:Aluminum / Q000097:blood*; D001665:Binding Sites; D006801:Humans; D007700:Kinetics; D011485:Protein Binding; D013056:Spectrophotometry, Ultraviolet; D014168:Transferrin / Q000378:metabolism*
chemical_list: D014168:Transferrin; D000535:Aluminum