Lysosomes are digestive compartments. A lysosome is a membrane-bound sac of hydrolytic enzymes that an animal cell uses to digest macromolecules. Lysosomal enzymes can hydrolyze proteins, fats, polysaccharides, and nucleic acids. These enzymes work best at pH 5. Proteins in the lysosomal membrane pump hydrogen ions from the cytosol into the lumen of the lysosomes. Rupture of one or a few lysosomes has little impact on a cell because the lysosomal enzymes are not very active at the neutral pH of the cytosol. However, massive rupture of many lysosomes can destroy a cell by autodigestion. Lysosomal enzymes and membrane are synthesized by rough ER and then transferred to the Golgi apparatus for further modification. Proteins on the inner surface of the lysosomal membrane are spared by digestion by their three-dimensional conformations, which protect vulnerable bonds from hydrolysis.
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This note was uploaded on 01/04/2012 for the course BSC BSC1005 taught by Professor Orlando,rebecca during the Fall '10 term at Broward College.