Lysozyme Function — MFDS Part 1 MCQ
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Correct answer: A — Hydrolysis of peptidoglycan in bacterial cell walls
Lysozyme is an innate antimicrobial enzyme in saliva. It hydrolyses the β-(1,4)-glycosidic bond between N-acetylmuramic acid and N-acetylglucosamine in bacterial cell-wall peptidoglycan, weakening the wall and promoting bacterial lysis. Peptidoglycan is more accessible in Gram-positive organisms, which are therefore generally more susceptible. Starch digestion is principally mediated by salivary α-amylase. Calcium binding and maintenance of mineral supersaturation involve proteins such as statherin and acidic proline-rich proteins. Acid neutralisation is mainly provided by bicarbonate and phosphate buffer systems, while mucins create the viscoelastic coating responsible for lubrication of the oral mucosa.
Reference: Liu H et al. Structure and function of human-derived lysozyme: a review. Sheng Wu Gong Cheng Xue Bao. 2023. https://pubmed.ncbi.nlm.nih.gov/38013179/