(a) Plots of velocity (V) of oxidized ABTS formation versus ABTS concentration (ABTS) with melamine concentration ranged from 0.5–2 mM. (b) Lineweaver-Burk plots of velocity (V) of oxidized ABTS formation versus ABTS concentration (ABTS) with melamine concentration ranged from 0.5–2 mM showing noncompetitive inhibition.