Galactosylceramidase (GALC) (also known as galactocerebrosidase) is a hydrolase [1] that removes galactose from galactosylceramide and other sphingolipids[2]. Galactosylceramidase in humans is encoded by the gene GALC, and mutations in this gene are associated with Krabbe disease, or globoid cell leukodystrophy[3].
| EC number
| 3.2.1.46
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| CAS number
| 158021-47-7
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| ExPASy
| [put ExPASy link here]
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| BRENDA
| [put BRENDA link here]
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| PDB
| 3ZR5
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| theoretical extinction coefficient
| 195,860 1/(M cm)
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| theoretical molecular weight
| 77.3 kDa
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| theoretical pI
| 6.27
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Structure
X-ray diffraction data () from mouse models indicates that GALC is an estimated 77 kDa protein consisting of 656 residues, which form a secondary structure containing 12 α-helices and 41 β-strands. Each β-strand contains three to eleven residues.
Use this link to by group, and this link to view a of the protein.
Function
Disease
Defects in this enzyme cause a lysosomal storage disorder known in humans as Krabbe disease (or globoid cell leukodystrophy). Krabbe disease is a neurodegenerative disorder characterized by widespread demyelination caused by reduced or mutated function of GALC[3]. The deficiency of GALC leads to the accumulation of the neurotoxic metabolite 1-β-d-galactosylsphingosine (psychosine) in the central nervous system. Psychosine causes the destruction of epithelial actin structures and is toxic to oligodendrocytes[4][5]. GALC deficiency also causes the accumulation of lipids in "globoid" macrophages, where the medical name for the disease originated[5]. A common authentic model for this disease is the twitcher mouse model[4]. The only treatment currently available is an experiemental hematopoietic stem cell transplant, and gene therapies and enzyme replacements are still being researched[5].
Relevance
