Influence of ultrasound to the activity of tyrosinase

The influence of ultrasound to the activity of tyrosinase was investigated. According to the analyses of ultraviolet-visible spectrometry and Fourier transform infrared spectroscopy, both monophenolase and diphenolase activities of tyrosinase treated by ultrasound were higher than that of control, with the decrease of lag time and the increase of activity. No oxytyrosinase was observed and beta-sheet conformation was predominant in the tyrosinase under ultrasound treatment. Moreover, with the observation of atomic force microscopy, the large molecular groups of tyrosinase were broken into small ones under the treatment of ultrasound. The present result suggested the activity of tyrosinase could be activated under the tested ultrasound treatment, mainly due to the increased likelihood of the combination of substrate and enzyme, or the possible change and exposure of the active site in tyrosinase. (C) 2012 Elsevier B.V. All rights reserved.