Fig. 1

The CAT activity enzyme showed an inverse correlation with the intensity of the Cu(I)-neocuproine complex. A solution with an appropriate concentration of H₂O₂ was used to reduce (Cu(Nc)₂²⁺) and produce a colored Cu(I)-neocuproine complex (Cu(Nc)₂⁺). The resulting complex was analyzed, and absorption spectra (a–f) were obtained for various H₂O₂ concentrations. The spectra (a–f) are a 5 mM, b 4 mM, c 3 mM, d 1 mM, e 0.5 mM, and f 0.1 mM