On the formation and role of reactive oxygen species in light-driven LPMO oxidation of phosphoric acid swollen cellulose.
Light-driven activation of lytic polysaccharide monooxygenases (LPMOs) has been attributed to the transfer of high redox potential electrons from excited photopigments to the enzyme. However, due to the formation of reactive oxygen species (ROS) in such a system, not only electrons from the pigments but also ROS could be part of the enzyme mechanism. This work investigates the role of ROS in the oxidation of phosphoric acid swollen cellulose (PASC) by a light-driven LPMO system. Our results clearly show that the addition of superoxide dismutase or catalase to remove ROS did not attenuate the capacity of the light-driven LPMO system to oxidize PASC, as measured by formation of oxidized oligosaccharides. We conclude that ROS are not part of the light-driven LPMO activation; hence, transfer of high redox potential electrons from the excited photopigment to the LPMO remains the most likely mechanism under the conditions tested in this study.
Department of Geoscience and Natural Resources, University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark.
K B
KB
Möllers
Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark.
H
H
Mikkelsen
Department of Geoscience and Natural Resources, University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark.
T I
TI
Simonsen
Department of Geoscience and Natural Resources, University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark.
D
D
Cannella
Department of Geoscience and Natural Resources, University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark.
K S
KS
Johansen
Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark.
M J
MJ
Bjerrum
Department of Geoscience and Natural Resources, University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark. Electronic address: cf@ign.ku.dk.
C
C
Felby
D002482:Cellulose / Q000737:chemistry* / Q000378:metabolism*; D008027:Light; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000528:radiation effects; D010756:Phosphoric Acids / Q000737:chemistry*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D020037:Sordariales / Q000201:enzymology
D010756:Phosphoric Acids; D017382:Reactive Oxygen Species; D002482:Cellulose; C030242:phosphoric acid; D006899:Mixed Function Oxygenases
Cellulose oxidation; Hydrogen peroxide; Lytic polysaccharide monooxygenases; Photopigments; Reactive oxygen species (ROS); Superoxide