CELLOBIOSE DEHYDROGENASE FROM SCHIZOPHYLLUM-COMMUNE - PURIFICATION AND STUDY OF SOME CATALYTIC, INACTIVATION, AND CELLULOSE-BINDING PROPERTIES

Cellobiose dehydrogenase (CDH) of Schizophyllum commune was purified t o homogeneity. It is a glycoprotein with a molecular mass of 102,000, Cellulosic substrates can serve as substrates for CDH. Cytochrome c, d ichlorophenol-indophenol, ferricyanide, and oxygen can be reduced by t he enzyme. CDH is stable in the pH range of 4-11 and up to 35 degrees C. The enzyme keeps active at high concentrations of H2O2. In the pres ence of cellobiose and Fe3+, incubation of CDH resulted in its inactiv ation and the degree of the inactivation was dependent mainly on the a mount of CDH and cellobiose present. CDH has a distinct and specific a ffinity to cellulose and showed the strongest binding to acid-treated cellulose. The adsorption isotherm data fitted the Langmuir-type equat ion. The uv-visible spectra of the oxidized and reduced states of CDH showed a typical cytochrome b-type pattern. Addition of dithionite eli minated the adsorption between 440 and 500 nm, which indicates the pre sence of a flavin group in CDH. (C) 1998 Academic Press.