1,4-β-d-Glucan cellobiohydrolase from Sclerotium rolfsii

Publisher Summary The fungus Sclerotium rolfsii , when grown on cellulose as the sole carbon source, produces an oxidative enzyme, cellobiose dehydrogenase, and three different types of hydrolytic enzymes: (1) a 1,4-β-D-glucan cellobiohydrolase, (2) three endo-fl-glucanases, and (3) four β-D-glucosidases. All these enzymes have been obtained in a homogeneous state. The hydrolytic enzymes form the cellulase complex of S. rolfsii. This chapter focuses on 1,4-β-D-glucan cellobiohydrolase from S. rolfsii . 1,4-β-D-Glucan cellobiohydrolase shows high activity toward phosphoric acid-swollen cellulose but no viscosity-lowering activity toward carboxymethylcellulose. It functions in the hydrolysis of crystalline cellulose. The enzyme acts in an endwise fashion by removing successive cellobiosyl units from the nonreducing end of the β-l,4-glucan chains; glucose is also detected. In addition, it shows an initial endo-type mode of action on cotton sliver producing short fibers. A similar type of enzyme that shows an endotype mode of action on crystalline cellulose has been reported in Trichoderma reesei.