Lysozyme is an enzyme (a type of protein) found in human tears, mucus, and saliva. It acts as a defense against bacteria by cleaving the polysaccharide chains in their cell walls. Its secondary structure, which consists of α helices and β sheets, is determined by hydrogen bonding. Its tertiary structure, its specific three-dimensional shape, is formed by the interactions between amino acid side chains. The active site is shown with a substrate bound to it. (2.3 MB)
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