What is the pH of lysosomes?

Lysosomes have an acidic pH, typically around 4.5, which is maintained by proton pumps in the lysosomal membrane. The low pH is crucial for the optimal functioning of the hydrolytic enzymes within lysosomes, which are responsible for breaking down and digesting various biomolecules. The enzymes are only active at low pH levels, so maintaining an acidic environment within lysosomes is essential for their proper function.