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α-galactosidase
α-Galactosidase tetramer, Mortierella vinacea
Identifiers
EC no. 3.2.1.22
CAS no. 9025-35-8
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / QuickGO
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PMC articles
PubMed articles
NCBI proteins

α-Galactosidase ( EC 3.2.1.22, α-GAL, α-GAL A; systematic name α-D-galactoside galactohydrolase) is a glycoside hydrolase enzyme that catalyses the following reaction: [1]

Hydrolysis of terminal, non-reducing α-D-galactose residues in α-D-galactosides, including galactose oligosaccharides, galactomannans and galactolipids

It catalyzes many catabolic processes, including cleavage of glycoproteins, glycolipids, and polysaccharides.

The enzyme is encoded by the GLA gene. [2]

Function

This enzyme is a homodimeric glycoprotein that hydrolyses the terminal α-galactosyl moieties from glycolipids and glycoproteins. It predominantly hydrolyzes ceramide trihexoside, and it can catalyze the hydrolysis of melibiose into galactose and glucose.[ citation needed]

Reaction mechanism

A double displacement reaction mechanism of α-GAL's catalytic action.The ligand (black) when bound in the active site of the enzyme (blue). The two key amino acid residues in the active site are Asp-170 and Asp-231. First, Asp-170 performs a nucleophilic attack on the glycosidic bond to release the terminal α-galactose molecule from the ligand. Then, Asp-231 serves as an acid to remove a proton from water, making it more nucleophilic to attack the galactose-Asp complex and release α-galactose from the active site. [3] [4] [5]

See also

References

  1. ^ Scriver CR, Sly WS, Childs B, ABeaudet AL, Valle D, Kinzler KW, et al. (15 December 2000). The Metabolic & Molecular Basis of Inherited Disease (8th ed.). McGraw-Hill. ISBN  978-0-07-913035-8.
  2. ^ Calhoun DH, Bishop DF, Bernstein HS, Quinn M, Hantzopoulos P, Desnick RJ (November 1985). "Fabry disease: isolation of a cDNA clone encoding human α-galactosidase A". Proceedings of the National Academy of Sciences of the United States of America. 82 (21): 7364–8. Bibcode: 1985PNAS...82.7364C. doi: 10.1073/pnas.82.21.7364. PMC  391345. PMID  2997789.
  3. ^ Koshland DE (1953). "Stereochemistry and the Mechanism of Enzymatic Reactions". Biological Reviews. 28 (4): 416–436. doi: 10.1111/j.1469-185x.1953.tb01386.x. S2CID  86709302.
  4. ^ Brumer H, Sims PF, Sinnott ML (April 1999). "Lignocellulose degradation by Phanerochaete chrysosporium: purification and characterization of the main α-galactosidase". The Biochemical Journal. 339 (1): 43–53. doi: 10.1042/bj3390043. PMC  1220126. PMID  10085226.
  5. ^ Vocadlo DJ, Davies GJ (October 2008). "Mechanistic insights into glycosidase chemistry". Current Opinion in Chemical Biology. 12 (5): 539–55. doi: 10.1016/j.cbpa.2008.05.010. PMID  18558099.

External links

This article incorporates text from the United States National Library of Medicine, which is in the public domain.