Electrochemical properties and temperature dependence of a recombinant laccase from Thermus thermophilus

Xin Liu, Megan Gillespie, Ayca Demirel Ozel, Emre Dikici, Sylvia Daunert, Leonidas G. Bachas

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

The electrochemical properties of a laccase from Thermus thermophilus HB27 (Tth-laccase) were characterized. The gene encoding the laccase was cloned and overexpressed in Escherichia coli. One-step purification of the corresponding apo-enzyme was achieved by nickel-affinity chromatography. Copper was incorporated into the apo-laccase as the cofactor to yield the holo-enzyme. The temperature-dependent catalytic activity of the laccase was investigated by spectrophotometric as well as electrochemical methods. Specifically, the catalytic properties of the enzyme were characterized by employing a photometric assay based on the oxidation of the substrate 2,2-azino-bis-(3- ethylbenzthiazoline-6-sulfonate) (ABTS). The electroactive substrate ABTS can be also monitored by cyclic voltammetry, thus allowing for determination of the enzymatic activity electrochemically. It was found that the recombinant laccase exhibited higher activity as the temperature increased up to 65 °C. Spectroscopic studies of Tth-laccase based on circular dichroism and fluorescence measurements are consistent with a thermally stable secondary structure of the protein.

Original languageEnglish (US)
Pages (from-to)361-366
Number of pages6
JournalAnalytical and bioanalytical chemistry
Volume399
Issue number1
DOIs
StatePublished - Jan 2011

Keywords

  • Electrochemistry
  • Enzyme
  • Laccase
  • Thermophilic
  • Thermus thermophilus

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry

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