Properties of native and hydrophobic laccases immobilized in the liquid-crystalline cubic phase on electrodes |
| |
Authors: | Ewa?Nazaruk Agnieszka?Michota Jolanta?Bukowska Sergey?Shleev Lo?Gorton Email author" target="_blank">Renata?BilewiczEmail author |
| |
Institution: | 1.Faculty of Chemistry,University of Warsaw,Warsaw,Poland;2.Department of Analytical Chemistry,Lund University,Lund,Sweden |
| |
Abstract: | Both native Trametes hirsuta laccase and the same laccase modified with palmytic chains to turn it more hydrophobic were prepared and studied with cyclic
voltammetry and Raman spectroscopy. Native laccase immobilized in the monoolein cubic phase was characterized with resonance
Raman spectroscopy, which demonstrated that the structure at the “blue” copper site of the protein remained intact. The diamond-type
monoolein cubic phase prevents denaturation of enzymes on the electrode surface and provides contact of the enzyme with the
electrode either directly or through the mediation by electroactive probes. Direct electron transfer for both laccases incorporated
into a lyotropic liquid crystal was obtained under anaerobic conditions, whereas bioelectrocatalytic activity was shown only
for the native enzyme. The differences in electrochemical behavior of native and hydrophobic laccase as well as possible mechanisms
of direct and mediated electron transfers are discussed. The Michaelis constant for 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate)
diammonium salt (ABTS2−), K
Mapp, and the maximal current, I
max, for the native enzyme immobilized onto the electrode were estimated to be 0.24 mM, and 5.3 μA, respectively. The maximal
current density and the efficiency of the catalysis, I
max/K
Mapp, were found to be 73 μA cm−2 and 208.2 μA cm−2 mM−1, respectively, and indicated a high efficiency of oxygen electroreduction by the enzyme in the presence of ABTS2− in the cubic-phase environment. Rate constants were calculated to be 7.5 × 104 and 3.6 × 104 M−1 s−1 for native and hydrophobic laccase, respectively. |
| |
Keywords: | Laccase Voltammetry 2 2′ -Azinobis(3-ethylbenzothiazoline-6-sulfonate) diammonium salt Oxygen reduction |
本文献已被 SpringerLink 等数据库收录! |
|