Beta-galactosidases hydrolyse mobilized GM1 to mobilized GM2

Stable Identifier
Reaction [transition]
Homo sapiens
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The prototypical ganglioside GM1 is hydrolyzed to the GM2 ganglioside by beta-galactosidase (GLB1), cleaving off the terminal galactose (Asp et al. 1969). Either Saposin B (PSAP(195-273)) or ganglioside GM2 activator (GM2A, GM2AP) acts as a cofactor (Wilkening et al., 2000). Defects in GLB1 cause the lysosomal storage diseases GM1-gangliosidosis (Yoshida et al. 1991; reviewed in Brunetti-Pierri & Scaglia, 2008) and Morquio syndrome B (Oshima et al. 1991). GLB1L, GLB1L2, and GLB1L3 are gene products with nearly identical protein sequences to GLB1 and may be able to perform the same function.
Literature References
PubMed ID Title Journal Year
18524657 GM1 gangliosidosis: review of clinical, molecular, and therapeutic aspects

Scaglia, F, Brunetti-Pierri, N

Mol Genet Metab 2008
10942779 Degradation of membrane-bound ganglioside GM1. Stimulation by bis(monoacylglycero)phosphate and the activator proteins SAP-B and GM2-AP

Wilkening, G, Linke, T, Uhlhorn-Dierks, G, Sandhoff, K

J Biol Chem 2000
5822067 Human small-intestinal beta-galactosidases. Separation and characterization of one lactase and one hetero beta-galactosidase

KoldovskĆ½, O, Asp, NG, Dahlqvist, A

Biochem J 1969
1907800 Human beta-galactosidase gene mutations in GM1-gangliosidosis: a common mutation among Japanese adult/chronic cases

Fukuhara, Y, Yoshida, K, Suzuki, Y, Sakuraba, H, Oshima, A, Yanagisawa, N, Shimmoto, M

Am J Hum Genet 1991
Catalyst Activity

beta-galactosidase activity of BGAL [lysosomal lumen]

Orthologous Events
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