It is an important and almost ubiquitous enzyme. It functionsenzymatically by breaking down bacterial cell walls, which kills the bacteria and helps keep us healthy. Procedures used to purify egg white lysozyme are the same as thoseused to purify engineered proteins from recombinant bacteria. Lysozyme is easy to assay. We will start by assaying lysozyme activity in our Egg White Preparation.
Lysozyme cleaves bonds between the subunits of cell wall polysaccharides in bacteria.
When the cell wall of a bacterium is ruptured, the contents of the cell are released and the cell falls apart. This gives us a way to measure the activity of lysozyme. When their cell walls are broken, the contents released consist mostly of water-soluble molecules. Most of the molecules then dissolve, and as the cells break, the cloudy suspension becomes a clear solution, which absorbs much less light at 450 nm than a suspension of cells. This change is visible to the naked eye, but we can get a more accurate reading of the enzyme's activity if we use a spectrophotometer.