Cellobiose dehydrogenase (CDH) (CDH)

Cellobiose dehydrogenase (CDH) is an extracellular hemoflavoenzyme primarily secreted by wood-degrading and plant-pathogenic fungi within the Basidiomycota and Ascomycota phyla [1, 8]. It plays a pivotal biological role in the degradation of lignocellulosic biomass by performing the oxidative breakdown of cellobiose and providing the necessary reducing power for lytic polysaccharide monooxygenases (LPMOs) to cleave crystalline cellulose [7, 8]. Structurally, the enzyme consists of a larger FAD-binding catalytic domain and a smaller cytochrome b domain, a configuration that allows for efficient inter-domain electron transfer and direct communication with electrode surfaces [3, 9]. While not a conventional therapeutic drug target in human physiology, CDH is highly significant in clinical diagnostics as a core component of third-generation electrochemical biosensors [1, 6]. Its ability to undergo direct electron transfer (DET) makes it ideal for the reagentless sensing of glucose and lactose, which is essential for monitoring conditions such as diabetes and lactose intolerance [4, 5]. Currently, there are no pharmaceutical drugs designed to inhibit or activate this enzyme for the treatment of human disease, and its primary utility remains in industrial biotechnology and advanced medical monitoring devices [8, 9].

Other names

Cellobiose oxidaseCellobiose-quinone oxidoreductaseCellobiose:acceptor 1-oxidoreductaseCBOR

Cellobiose dehydrogenase catalyzes the oxidation of cellobiose and other cello-oligosaccharides to their corresponding 1,5-lactones. The reaction involves a two-step internal electron transfer: the substrate first reduces the FAD cofactor in the catalytic dehydrogenase (DH) domain, and the resulting electrons are then transferred via a flexible linker to the heme b cofactor in the cytochrome (CYT) domain. From the CYT domain, electrons are passed to external acceptors, such as lytic polysaccharide monooxygenases (LPMOs) in nature, or electrode surfaces in biosensor applications.