Lysosome
A lysosomes are membrane bound organelles found in eukaryotic cells. They were first discovered by the belgian cytologist 'Christian Rene de duve' in the 1950s .[1]
Lysosomes contain up to 40 different types of hydrolytic enzymes which control the digestion of macromolecules, such as nucleic acids and proteins, old cell parts, and other foriegn pathogens. Some of the most common lysosomal enzymes include proteases, nucleases, glycosidases, lipases, phospolipases, phosphatases and sulfatases which are all acid hydrolases. [2] These enzymes optimum pH is at 4.5 - 5.5 which, compared to the cytosols pH of 7.2, is very acidic. The acidic pH of the lumen is maintained by a vacular ATPase proton pump which pumps H+ Into the lysosome. These conditions help protect the cell from possible 'leakages', as the hydrolytic enzymes would not be able to function in the neutral pH of the cytosol.
References:
- ↑ http://www.britannica.com/EBchecked/topic/174733/Christian-Rene-de-Duve?anchor=ref23999
- ↑ Bruce Alberts [et al] "Molecular biology of the cell" 5th edition.