phosphomannomutase activity

Definition

Target type: molecularfunction

Catalysis of the reaction: alpha-D-mannose 1-phosphate = D-mannose 6-phosphate. [EC:5.4.2.8, RHEA:11140]

Phosphomannomutase activity catalyzes the reversible isomerization of mannose-6-phosphate to mannose-1-phosphate. This reaction is essential for the biosynthesis of GDP-mannose, a key precursor for the synthesis of numerous glycoconjugates, including N-linked glycans, O-linked glycans, and glycosphingolipids. The enzyme utilizes a two-step mechanism involving a phosphorylated enzyme intermediate. In the first step, the enzyme transfers a phosphate group from a donor molecule, typically a phosphoenzyme, to the hydroxyl group at the C-6 position of mannose-6-phosphate. This results in the formation of mannose-1,6-bisphosphate. In the second step, the enzyme removes the phosphate group from the C-6 position and transfers it to the hydroxyl group at the C-1 position, yielding mannose-1-phosphate. The enzyme's active site contains a conserved histidine residue that plays a critical role in the catalytic process by acting as a general base for the deprotonation of the hydroxyl group at C-6 and a general acid for the protonation of the hydroxyl group at C-1. Phosphomannomutase activity is essential for normal cellular function and is involved in a wide range of biological processes, including protein glycosylation, cell signaling, and immune response.'
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Proteins (2)

Compounds (10)