Enzymes needed by the lysosomes are synthesized and produced in the rough endoplasmic reticulum. Lysosomes contain more than sixty different enzymes. 

In the rough endoplasmic reticulum (RER), enzymes destined for a lysosome undergo specific post-translational modifications such as phosphorylation and glycosylation. The modified enzymes, known as lysosomal enzymes, are transported from the RER to the Golgi apparatus for further processing and packaging into vesicles which are then imported into lysosomes.