VOLTAMMETRIC BEHAVIOR STUDIES ON THE INTE RACTION BETWEEN LANTHANIDE IONS AND NAD(-LDH COMPLEX(), NAD)

Voltammetric behavior studies on the interaction of Ln(3+) ions with N AD(+) and NAD-LDH complex were presented. The results showed that Ln(3 +) interacted with NAD(+) by dividing the reduction wave of NAD(+) at -0.94 V into two waves, which could be attributed to the binding of Ln (3+) ions with the pyrophosphorous moiety of NAD(+). The effect of Ln( 3+) ions on NAD(+) was progressively eliminated by adding EDTA. On mer cury electrode NAD(+) formed a complex with LDH and was reduced at -1. 16 V. The dissociation constant of NAD-LDH was determined. When NAD-LD H complex was formed, the addition of 5 mu mol/L La3+, Ce3+, Pr3+, Eu3 +, Gd3+, Dy3+, Yb3+, Lu3+ respectively increased the dissociation cons tant of NAD-LDH complex in the range of 40%similar to 70%. These resul ts could be used as an explanation for the inhibition of Ln(3+) ions o n LDH activity.