Mechanisms of redox interactions between lignin peroxidase and cellobiose:quinone oxidoreductase.
The mechanism of redox interactions between the heme-enzyme, lignin peroxidase (LiP), and the FAD-enzyme, cellobiose:quinone oxidoreductase (CBQ) (EC 1.1.5.1), was investigated under various conditions. Veratryl alcohol oxidation by LiP was inhibited by CBQ in the presence of cellobiose. Lineweaver-Burk plots at various CBQ concentrations suggest that this inhibition is non-competitive. The oxidation rate of the reduced CBQ (FADH2) by LiP plus H2O2 increased significantly only in the presence of veratryl alcohol. Furthermore, the cation radical derived from 1,2,4,5-tetramethoxybenzene was reduced by CBQ in the presence of cellobiose. It is concluded from these results that CBQ can reduce aromatic cation radicals and that veratryl alcohol acts as a radical mediator of the redox interactions between LiP and CBQ.
Samejima
M
M
Department of Biochemistry, University of Georgia, Athens 30602.
Eriksson
K E
KE
D002237:Carbohydrate Dehydrogenases / Q000378:metabolism*; D002412:Cations; D010084:Oxidation-Reduction; D010544:Peroxidases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013175:Sporothrix / Q000201:enzymology
D002412:Cations; D002237:Carbohydrate Dehydrogenases; C019859:cellobiose-quinone oxidoreductase; D010544:Peroxidases; C042858:lignin peroxidase