Lysozyme is an antibacterial enzyme first identified in 1921 by Alexander Fleming, the scientist who discovered penicillin. Lysozyme catalyses hydrolysis of glycosidic bonds in peptidoglycan molecules, producing the smaller products NAG (N-acetylglucosamine) and NAM (N-acetylmuramic acid).
(a)[3]
Draw labelled and annotated diagrams in the space provided to illustrate how the lock and key hypothesis was applied to explain the mechanism of action of lysozyme on peptidoglycan.
(b)[3]
Compare lysozyme with penicillin to highlight the similarities and differences between these two antibacterial agents.
Worked solution & mark scheme
This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: “The enzyme active site has a specific complementary shape to the substrate.” …