Redox regulation of enzyme activity during wood decay

IRG/WP 96-10172

P J Kersten, B Kurek, J W Whittaker

A potential strategy in the search for alternative wood preservatives against fungal decay is to target the extracellular wood-decay process itself, rather than the decay organisms. This presents novel targets for selective disruption and possibly without the broad-spectrum toxicity associated with conventional wood preservatives. The enzymes of white rot decay are mechanistically diverse (e.g. hydrolytic, oxidative, peroxidative) and therefore various strategies for the disruption of their activity can be conceptualized. We have characterized how effectors control activity of the extracellular enzyme glyoxal oxidase. This enzyme is secreted by Phanerochaete chrysosporium and produces hydrogen peroxide required by ligninolytic peroxidases. Our studies with recombinant glyoxal oxidase show that the native enzyme is activated by inorganic oxidants or by lignin peroxidase when peroxidase substrates of high redox potential are used. The interconversion between active and inactive forms of the enzyme is defined in redox terms based on spectroelectrochemical measurements of the active site of glyoxal oxidase.


Keywords: ENZYME INACTIVATION; WHITE ROT; PEROXIDE

Conference: 96-05-19/24 Guadeloupe, France


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