The correct targeting of newly synthesized hydrolytic enzymes to the lysosomes requires which of the following modifications?
A) attachment of mannose 6-phosphate to the enzymes
B) g-Carboxylation of glutamate residues in the enzymes
C) O-linkage of carbohydrate to the enzymes
D) prenylation of the enzymes
E) proteolytic activation following transport to the lysosome

Question

Quizplus · Accepted Answer

The attachment of mannose 6-phosphate to enzymes is crucial for their recognition and transport to lysosomes. This modification occurs in the Golgi apparatus and is essential for the proper targeting of lysosomal enzymes.  Enzymes that are destined for the lysosomes (lysosomal enzymes) are directed there by a specific carbohydrate modification. During transit through the Golgi apparatus, a residue of GlcNAc-1-phosphate (GlcNAc-1-P) is added to the carbon-6 hydroxyl group of one or more specific mannose residues that have been added to these enzymes. A specific Man-6-P receptor (MPR) is present in the membranes of the Golgi apparatus. Binding of Man-6-P to this receptor targets proteins to the lysosomes.

The Correct Targeting of Newly Synthesized Hydrolytic Enzymes to the Lysosomes