Reactome | NPL cleaves Neu5Ac,Neu5Gc to ManNAc,ManNGc and pyruvate

NPL cleaves Neu5Ac,Neu5Gc to ManNAc,ManNGc and pyruvate

Stable Identifier

R-HSA-4085217

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)
        
        Sialic acid metabolism (Homo sapiens)
        
        NPL cleaves Neu5Ac,Neu5Gc to ManNAc,ManNGc and pyruvate (Homo sapiens)

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NPL cleaves Neu5Ac,Neu5Gc to ManNAc,ManNGc and pyruvate

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Once in the cytosol, sialic acids are either reutilized or degraded. N-acetylneuraminate lyase (NPL) is a cytosolic, tetrameric enzyme that can cleave the major sialic acids N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc) to form N-acetylmannosamine (ManNAc) and N-glycolylmannosamine (ManNGc) respectively (Wu et al. 2005). Although humans cannot form Neu5Gc due to a non-functional CMAHP enzyme, Neu5Gc can be ingested by dietary means and must therefore be degraded to avoid accumulation of this immunoreactive sialic acid (Bergfeld et al. 2012).

Literature References

PubMed ID	Title	Journal	Year
22692205	Metabolism of vertebrate amino sugars with N-glycolyl groups: elucidating the intracellular fate of the non-human sialic acid N-glycolylneuraminic acid Pearce, OM, Pham, T, Diaz, SL, Varki, A, Bergfeld, AK	J. Biol. Chem.	2012
16147865	A novel splice variant of human gene NPL, mainly expressed in human liver, kidney and peripheral blood leukocyte Xu, J, Gu, S, Zou, X, Xie, Y, Mao, Y, Ji, C, Zheng, H, Jin, Z, Wu, M	DNA Seq.	2005