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galactosylceramidase; galactosylceramide beta-galactosidase; galactocerebroside beta-galactosidase; galactosylceraminidase; galactocerebrosidase (GALC)
Function:
- hydrolyzes the galactose ester bonds of galactosylceramide, galactosylsphingosine, lactosylceramide, & monogalactosyldiglyceride
- enzyme with very low activity responsible for the lysosomal catabolism of galactosylceramide, a major lipid in myelin, kidney & epithelial cells of small intestine & colon
D-galactosyl-N-acylsphingosine + H2O
D-galactose + N-acylsphingosine
Kinetic parameters:
- Optimum pH is 4.0-4.4
- Temperature dependence: activity is lost after heating at 52 degrees C for 5 minutes
Structure: belongs to the glycosyl hydrolase 59 family
Compartment: Lysosome
Alternative splicing: named isoforms=2
Expression:
- highest level of activity in testes compared to brain, kidney, placenta & liver
- also be found in urine
Polymorphism:
- polymorphic amino-acid changes are responsible for the wide range of catalytic activities found in the general population
Pathology:
- mutations associated with globoid cell leukodystrophy (GLD) or Krabbe disease
Laboratory:
- GALC gene mutation
- galactosylceramidase in amniotic fluid
- galactosylceramidase in dried blood spot
- galactosylceramidase in fibroblasts
- galactosylceramidase in leukocytes
- galactosylceramidase in tissue
General
galactosidase
glycoprotein
Properties
SIZE: entity length = 669 aa
MW = 75 kD
COMPARTMENT: lysosome
MOTIF: signal sequence {1-26}
N-glycosylation site {N127}
N-glycosylation site {N363}
N-glycosylation site {N387}
N-glycosylation site {N540}
N-glycosylation site {N543}
N-glycosylation site {N586}
Database Correlations
OMIM correlations
MORBIDMAP 606890
UniProt P54803
Pfam PF02057
Entrez Gene 2581
ENZYME 3.2.1.46
References
- OMIM :accession 245200
- Genedis; Krabbe disease website
http://life2.tau.ac.il/Genedis/Tables/Krabbe/krabbe.html
- GeneReviews
https://www.genecards.org/cgi-bin/carddisp.pl?gene=GALC
- UniProt :accession P54803