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).
Pearce, OM, Pham, T, Diaz, SL, Varki, A, Bergfeld, AK
Xu, J, Gu, S, Zou, X, Xie, Y, Mao, Y, Ji, C, Zheng, H, Jin, Z, Wu, M
N-acetylneuraminate lyase activity of NPL tetramer [cytosol]
© 2023 Reactome
