Study of absorbance and fluorescence properties of laccase and catechol solutions in the UV range

Laccase is an enzyme belonging to the oxidoreductase class and has copper atoms in the catalytic centre. The catalytic property of this enzyme consists of the enzymatic oxidation of the phenolic compounds, in the corresponding quinones, with the concomitant reduction of molecular oxygen to water. There is growing interest in developing innovative sensing methods for detecting phenolic substrates, such as catechol. Preliminary absorption and fluorescence measurements were carried out in the UV-Visible range to evaluate the possibility of using the variations produced in the spectra of laccase and/or catechol to monitor the presence of this substrate. The absorption and fluorescence emission increase upon UV excitation is detected. By monitoring the time course of the fluorescence signal, an evident increase in the signal detected in the UV range is observed until a saturation level is reached. The observed variations in the spectra, in the presence of the catechol, are discussed also in terms of the interactions between the enzyme and the phenolic compound. The results are very promising for the design of new optical detection methods for polyphenols pollutants.