Bifunctional UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase is an
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
that in humans is encoded by the ''GNE''
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
.
The bifunctional enzyme, UDP-N-acetylglucosamine 2-epimerase (UDP-GlcNAc 2-epimerase/N-acetylmannosamine kinase) regulates and initiates biosynthesis of N-acetylneuraminic acid (NeuAc), a precursor of sialic acids. UDP-GlcNAc 2-epimerase activity is rate-limiting for the biosynthesis of sialic acid and is required for sialylation in hematopoietic cells. The activity of the enzyme can be controlled at the transcriptional level and can affect the sialylation and function of specific cell surface molecules expressed on B cells and myeloid cells. Modification of cell surface molecules with sialic acid is crucial for their function in many biologic processes, including cell adhesion and signal transduction. Differential sialylation of cell surface molecules is also implicated in the tumorigenicity and metastatic behavior of malignant cells.
Sialuria is a rare inborn error of metabolism characterized by cytoplasmic accumulation and increased urinary excretion of free NeuAc.
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External links
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GeneReviews/NCBI/NIH/UW entry on Sialuria
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