New function of laccase from Trametes sp．SQ01:transforming 2-hydroxy-6-oxo-6-phenylhexa-2，4-dienoate

Abstract:

Abstract:［Objective］ To study the transformation of 2-hydroxy-6-oxo-6-phenylhexa-2，4-dienoates (HOPDAs) by laccase from Trametes sp．SQ01 so to further understand the new catalytic properties of laccase and solve the problem of accumulations of HOPDAs in polychlorinated biphenyls (PCBs) degradation. ［Methods］ With UV-vis spectrophotometer，we studied the transformations of 8 substituted HOPDAs by laccase，and measured the steady-state kinetics parameters of laccase against parts of HOPDAs.［Results］ Laccase catalyzed HOPDAs to colorless substances without any mediators; among them，especially 3，8，11-3Cl HOPDA that was barely transformed by 2-hydroxy-6-oxo-6-phenylhexa-2，4-dienoate hydrolase (BphD) and Rhodococcus sp．R04，also could be transformed by this laccase．The analysis of the steady-state kinetics indicated that 10-Cl HOPDA was the optimal substrate of laccase among 5 HOPDAs，and the Km was lower than that of HOPDA and 8-Cl HOPDA．Although 3，10-2F HOPDA was not the optimal substrate (Km=17.02 μmol/L)，its transformation efficiency (kcat/Km) was the highest.［Conclusion］Laccase from Trametes sp. SQ01could transform various HOPDAs effectively，and has its potential in eliminating PCB pollution.