Which enzyme would hydrolyze cellulose?

• A. Amylase
• B. Lipase
• C. Cellulase
• D. Peptidase

Answer: (C)

Cellulose is a plant polysaccharide made of long chains of glucose units joined by beta-1,4-glycosidic bonds. To break these beta linkages, you need an enzyme capable of hydrolyzing those specific bonds, which is cellulase. This enzyme is produced by certain fungi, bacteria, and some microorganisms in the guts of herbivores, enabling the digestion of plant material. Humans don’t produce significant cellulase, so cellulose isn’t easily digested, but in contexts where cellulolytic enzymes are present, they cleave the beta-1,4 bonds to yield glucose or smaller sugars like cellobiose. The other enzymes act on different substrates: amylase hydrolyzes starch, lipase digests fats, and peptidase cleaves peptide bonds in proteins. Thus, cellulase is the enzyme that hydrolyzes cellulose.