VPB 112: General Veterinary Biochemistry (1+1)

CELLULOSE

• The other major polysaccharides of plants, which serve as a structural rather than a nutritional role.
• It is a linear, unbranched homopolysaccharides of D- glucose.
• It resembles the structure of amylose, but there is a very important difference, the glucose residues are in the β - configuration, whereas in amylose, amylopectin and glycogen, glucose is in a - configuration.
• The glucose residues in cellulose are linked by β(1 4) linkages, which are not hydrolyzed by the amylases found in the digestive tract of humans or most other higher animals. Consequently, man and most animals cannot utilize the energy present in this glucose polymer.
• In ruminants and other herbivores, the bacteria that reside in the rumen secrete cellulase, - glucosidase, that catalyzes the hydrolysis of cellulose to glucose.
• The bacteria and others resident in the rumen then metabolize the glucose to volatile fatty acids that are beneficial to the host animals.