ISBN: 978-83-60043-10-3 - eurobic9

Eurobic9, 2-6 September, 2008, Wrocław, Poland
P24. Comparison of the Spectroscopic Characteristics of Two Different
Fungal Laccases
C. Bukh and M. J. Bjerrum
University of Copenhagen, Faculty of Life Sciences, Department of Natural Sciences, Thorvaldsensvej 40, DK-
1871 Frederiksberg C, Denmark
e-mail: bukh@life.ku.dk
Laccase (E.C. 1.10.3.2), a blue multi-copper oxidase found in many plants and fungi, catalyzes single electron
oxidation of a broad range of substrates, coupled to the four-electron reduction of dioxygen to water. Laccase
contains four copper ions in three fully conserved binding sites (T1, T3 and T2) and belongs to a sub-group of
the blue multi-copper oxidases (MCOs), which includes ascorbate oxidase, ceruloplasmin CotA and Fet3p.
Despite having fully conserved active copper binding domains, the absorption spectrum arising from the bluecopper
site differs among the different laccase species. We have studied the spectroscopic properties of several
fungal laccases as a function of pH. Furthermore a change in pH has been shown to cause a time dependent
change in the behavior of the evaluated laccases.
The responses to pH changes exhibited by different laccases will be presented using a combination of
spectroscopic techniques like UV-Vis, CD and EPR spectroscopy. Furthermore in silico models will be included
in the evaluation of the results.
Acknowledgement: The enzymes were kindly donated by Novozymes A/S, Bagsværd, Denmark. Jesper Bendix
is thanked for technical assistance with the EPR measurements. Danish Chemical Society for financial support to
this conference.
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