Principles of Biochemistry Volume 1 - A. Lehninger 1985

Biomolecules
Cells
Lysosomes - containers with hydrolytic enzymes

Lysosomes are membrane-bound spherical vesicles found in the Cell Cytoplasm (Fig. 2-14). Their size varies, but they typically do not exceed the size of Mitochondria. Lysosomes contain a variety of Enzymes capable of digesting—that is, breaking down via Hydrolysis—cellular Proteins, Polysaccharides, and Lipids that are no longer needed. Because these enzymes could also destroy the rest of The Cell's contents, they are safely enclosed within the lysosomes. Proteins and other components destined for degradation are selectively transported into the lysosomes, where they undergo hydrolytic Cleavage into their simplest building blocks, which are then recycled back into the cytoplasm. Individuals with the inherited Tay-Sachs disease lack certain lipid-hydrolyzing enzymes in their lysosomes, causing some of these compounds to accumulate in the Brain and other Tissues, leading to mental retardation.

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Fig. 2-14. Lysosomes and Peroxisomes are enzyme "sacs". A. A portion of an adrenal cortex cell. The dark, irregularly shaped oval bodies are lysosomes. They are smaller than mitochondria. Lysosomes contain over 40 hydrolytic enzymes; additionally, folds of "excess" membrane containing cellular proteins and other components are sometimes found within them. B. Peroxisome. The crystalline core consists of urate oxidase, one of several peroxide-producing enzymes found in peroxisomes.