Study on the binding of cerium(III) ion and spermine to TRNA(Phe).

Fluorescence of Ce(III) aqua ion at pH 6.0 is found to be in good linear relationship with its concentration, and the intensity is strong enough to be employed to determine its concentration. TRNA(Phe) evidently quench this fluorescence. Fluorescence titration experiments were performed to Ce(III)-tRNA(Phe) system, the binding number and association constant was estimated with a Scatchard plot. Two classes of binding sites with association constant of 5.2 x 10(7) and 4.4 x 10(6) M, respectively, were found. Addition of spermine slightly decrease binding number and association constant of Ce(III) ion.