The organelle that contains most of the hydrolytic enzymes in a cell is the lysosome. Lysosomes are relatively small, membrane-bound organelles that cells use for a variety of purposes including breaking down organic molecules, fighting organisms that cause disease, and repairing their cell membranes.
Lysosomes are vital to digestion within the cell, and use their enzymes to break down food items into forms that the cell can use. If there is insufficient food in the environment, the lysosomes are also capable of breaking down other organelles for the necessary materials. When used for defense, the lysosomes can destroy pathogens attacking a cell or, in animals, can be deployed by specialized immune cells to destroy pathogens that endanger different cells. These cells engulf pathogens and release the hydrolytic enzymes within lysosomes onto them.
The enzymes within lysosomes are dangerous to the cell that creates them. If the membrane of a lysosome were to leak, it could digest the cell itself. This membrane is made up of lipids, while the enzymes it contains are proteins. Lysosomes are generally found only in animal or animal-like cells. Plant cells generally do not have lysosomes, as their cell walls protect them from the dangers that lysosomes normally fight.