Cellulose Hydrolysis

Cellulase catalyzes the endohydrolysis of β−(1→4)-D-glucosidic linkages in cellulose, lichenin and cereal β-D-glucans
Most cellulase preparations contain various classes of cellulases and related activities.
  • The endo-β-(1→4)-D-glucanases (EGs) cleave cellulose in its internal non-terminal regions, yielding oligosaccharides
  • The two forms of cellobiohydrolases (CBH) are considered exo-β-(1→4)-D-glucanases, releasing cellobiose disaccharides from the cellulose chain reducing end (CBHI), and non-reducing end (CBHII)
  • β-Glucosidase is an exohydrolase that yields glucose monosaccharides from soluble oligosaccharaides such as cellobiose
Other activities that can be found in cellulase preparations include xylanase, hemicellulase, and laminarinase

Hemicelluloses are a group of plant-derived heteropolysaccharides associated with cellulose and lignin. The most common hemicelluloses are xylan, glucuronoxylan, arabinoxylan, glucomannan and xyloglucan. In angiosperms, the principal hemicellulose component, xylan, is a polymer of β−(1→4)-D-xylopyranose. In arabinoxylan, branching occurs at the C2 & C3 postions with a-L-arabinofunaose. Glucuronoxylan, also found in angiosperms, has the xylan backbone with 4-0 methylglucuronic acid branching. In addition, arabinose branching as well as acetylation may be present. Gymnosperms contain glucomannans comprised primarily of D-mannosyl and D-glucosyl residues..
  • Hemicellulase preparations are typically a mixture of glycolytic enzymes containing xylanase, mananase and other activities.
Xylanase catalyzes the endohydrolysis of β−(1→4)-D-xylosidic linkages in xylans yielding various β−(1→4)-D-xylooligosaccharides