Principles of Biochemistry (2+1)

3.3.3.4 Cellulose

Cellulose is the structural component of plant cell walls, it the most abundant naturally occuring polysachharide. It is insoluble and consists of D-glucopyranose units linked by ß(1-4) glycosidic bonds to form long, straight chains strengthened by cross-linked hydrogen bonds.

 

Cellulose cannot be digested by many mammals, including humans, because of the absence of an enzyme that attacks the β linkages. But, it is an important source of “bulk” in the diet. In the stomach of ruminants and other herbivores, there are microorganisms that can attack the β linkage, making cellulose available as a major calorigenic source.