Comparative Binding Studies of Titanium and Iron to Human Serum Transferrin Publisher



Aarabi MH¹ ; Mirhashemi SM¹ ; Ani M² ; Moshtaghie AA³ Show Affiliations
Source: Asian Journal of Biochemistry Published:2011

Abstract

It is believed that titanium may interfere with iron metabolism in terms of absorption, transportation, utilization and storage in the cells. The present investigation was designed to study and compare the binding of iron and titanium to human serum Apo transferrin (apo-htf). Present results show that Ti(III) ions bind to transferrin and form a new complex and the calculated apparent association constant is 1.03×lO7 M-1 based on the Equilibrium dialysis technique. The binding of both metals to apo-htf appears to be pH dependent, changing with both increase and decrease pH. Titration studies demonstrate that transferrin specifically binds two moles Ti(IV) as complex with citrate per mol protein, spectrophotometery technique indicated that Ti(IV) ions cause a 13% reduction in binding of Fe(III) to transferrin. These results show that titanium competes with iron in binding to apo-htf. Although, the binding sites for these two ions seem to be similar, the binding of iron to apo-htf seems tighter. © 2011 Academic Journals Inc.