Spectroscopic Studies on Titanium Ion Binding to the Apolactoferrin

Titanium (Ti) is a relatively abundant element that has found growing applications in medical science and recently some of Ti compounds are introduced as anticancer drugs. In spite of very limited data which exist on the Ti metabolism, some proteins might be involved in the mechanism of action of Ti. Up to our knowledge, there is not any report in the literature concerning binding of Ti to apolactoferrin. Binding of apolactoferrin with Ti(IV)-citrate was studied by spectroflourimeterey and spectrophotometery techniques under physiological conditions. The spectroflourimeteric studies revealed a significant fluorescence quenching, that indicated binding of apolactoferrin with Ti(IV). The same reaction was monitored through spectrophotometry technique this represents a characteristic UV difference band at 267 nm, which is different from lac-Fe (III). Titration studies show that lactoferrin specifically binds two moles Ti(IV) as complex with citrate per mol protein. Spectroflourimeterey and spectrophotometery techniques indicated that Ti(IV) ions cause a reduction (13%-14%) in binding of Fe(III) to lactoferrin. In overall, we may come to this conclusion that this element might be involved in the iron metabolism.