Reactome | RENBP isomerises ManNAc, ManNGc to GlcNAc, GlcNGc

RENBP isomerises ManNAc, ManNGc to GlcNAc, GlcNGc

Stable Identifier

R-HSA-6803761

Type

Reaction [transition]

Species

Homo sapiens

Compartment

cytosol

ReviewStatus

5/5

Locations in the PathwayBrowser

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Metabolism of proteins (Homo sapiens)

- Post-translational protein modification (Homo sapiens)
  - Asparagine N-linked glycosylation (Homo sapiens)
    - Biosynthesis of the N-glycan precursor (dolichol lipid-linked oligosaccharide, LLO) and transfer to a nascent protein (Homo sapiens)
      - Synthesis of substrates in N-glycan biosythesis (Homo sapiens)
        
        Synthesis of UDP-N-acetyl-glucosamine (Homo sapiens)
        
        RENBP isomerises ManNAc, ManNGc to GlcNAc, GlcNGc (Homo sapiens)

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RENBP isomerises ManNAc, ManNGc to GlcNAc, GlcNGc

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Humans are not able to catalyse the formation of N-glycolylneuraminic acid (Neu5Gc) due to an inactive CMAHP enzyme. Neu5Gc can be obtained from dietary sources and must be degraded to avoid accummulation and resultant chronic inflammation known as xenosialitis (Varki et al. 2011). Degradation of excess Neu5Gc results in the formation of two ubiquitous metabolites involved in asparagine N-linked glycosylation; glycolate and glucosamine 6-phosphate. In the Neu5Gc degradation pathway, N-acylglucosamine 2-epimerase (RENBP) dimer catalyses the reversible isomerisation of N-acetylmannosamine (ManNAc) to N-acetylglucosamine (GlcNAc) and of N-glycolylymannosamine (ManNGc) to N-glycolylglucosamine (GlcNGc) (Takahashi et al. 1999, 2001).

Literature References

PubMed ID	Title	Journal	Year
21073341	Biomedical differences between human and nonhuman hominids: potential roles for uniquely human aspects of sialic acid biology Varki, NM, Dick, EJ, Benirschke, K, Varki, A, Strobert, E	Annu Rev Pathol	2011
9990133	Human renin-binding protein is the enzyme N-acetyl-D-glucosamine 2-epimerase Takahashi, K, Ogasawara, H, Shindo, S, Kaneko, T, Takahashi, S, Kobayashi, M	J. Biochem.	1999
11726282	Effects of nucleotides on N-acetyl-d-glucosamine 2-epimerases (renin-binding proteins): comparative biochemical studies Takahashi, K, Hori, K, Ogasawara, H, Takahashi, S, Saito, K, Tomatsu, M	J. Biochem.	2001