Cellobiose dehydrogenase.

Abstract

Cellobiose dehydrogenase (CDH) is an extracellular hemoflavoenzyme secreted by fungi to assist lignocellulolytic enzymes in biomass degradation. Its catalytic flavodehydrogenase (DH) domain is a member of the glucose-methanol-choline oxidoreductase family similar to glucose oxidase. The catalytic domain is linked to an N-terminal electron transferring cytochrome (CYT) domain which interacts with lytic polysaccharide monooxygenase (LPMO) in oxidative cellulose and hemicellulose depolymerization. Based on CDH sequence analysis, four phylogenetic classes were defined. CDHs in these classes exhibit different structural and catalytic properties in regard to cellulose binding, substrate specificity, and the pH optima of their catalytic reaction or the interdomain electron transfer between the DH and CYT domain. The structure, reaction mechanism and kinetics of CDHs from Class-I and Class-II have been characterized in detail and recombinant expression allows the application in many areas, such as biosensors, biofuel cells biomass hydrolysis, biosynthetic processes, and the antimicrobial functionalization of surfaces.