Reaction: GLB1 hydrolyzes SapB/C:LacCer
- in pathway: Glycosphingolipid catabolism
Lactosylceramide (LacCer) is the central intermediate in glycosphingolipid catabolism. Beta-galactosidase (GLB1) cleaves the galactose moiety from LacCer to form glucosylceramide. LacCer accumulates in GLB1 deficiencies (MIM: 611458) like GM1-gangliosidosis but also in prosaposin deficiency (PSAPD, MIM: 611721), which shows saposin cofactors are essential for the reaction (Asp et al. 1969; Bradova et al., 1993). We follow Sandhoff & Sandhoff (2018), who state that Saposins B/C bind to LacCer.
Reaction - small molecule participants:
Gal [lysosomal lumen]
H2O [lysosomal lumen]
Reactome.org reaction link: R-HSA-1606312
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Reaction input - small molecules:
water
Reaction output - small molecules:
alpha-D-galactose
Reactome.org link: R-HSA-1606312