GALE - UDP-glucose 4-epimerase - human protein (Function)
 
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Protein
Gene
References

 
GALE »  UDP-glucose 4-epimerase   [ EC 5.1.3.2 ]
 
Protein also known as:  UDP-N-acetylgalactosamine 4-epimerase (UDP-GalNAc 4-epimerase).
Gene name:  GALE
Family name: Sugar epimerase
Entry whose protein(s) existence is based on evidence at protein level
extend overview
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GENE REF ISO

Function

 show evidences
Overview 
Catalyzes two distinct but analogous reactions: the reversible epimerization of UDP-glucose to UDP-galactose and the reversible epimerization of UDP-N-acetylglucosamine to UDP-N-acetylgalactosamine. The reaction with UDP-Gal plays a critical role in the Leloir pathway of galactose catabolism in which galactose is converted to the glycolytic intermediate glucose 6-phosphate. It contributes to the catabolism of dietary galactose and enables the endogenous biosynthesis of both UDP-Gal and UDP-GalNAc when exogenous sources are limited. Both UDP-sugar interconversions are important in the synthesis of glycoproteins and glycolipids.  
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  • UniProtKB
GO molecular function 
Coenzyme bindingdefinition[GO:0050662] silver  
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  • InterPro 2 GO
Protein homodimerization activitydefinition[GO:0042803]  
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  • UniProtKB
UDP-glucose 4-epimerase activitydefinition[GO:0003978]  
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  • UniProtKB
UDP-N-acetylglucosamine 4-epimerase activitydefinition[GO:0003974]  
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  • EC 2 GO
GO biological process 
Galactose catabolic processdefinition[GO:0019388]  
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  • UniProtKB
Enzymatic activity 
This protein acts as an enzyme. It is known to catalyze the following reactions
EC 5.1.3.2: UDP-alpha-D-glucose UDP-alpha-D-galactose.  
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  • UniProtKB
EC 5.1.3.7: UDP-N-acetyl-alpha-D-glucosamine UDP-N-acetyl-alpha-D-galactosamine.  
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  • UniProtKB
It requires the following cofactor
 NAD(+)  
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  • UniProtKB
 
More information is available from:
Pathways 
This protein is involved in the following pathway
Carbohydrate metabolism; galactose metabolism  
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  • UniProtKB
According to KEGG, this protein belongs to the following pathways:
Amino sugar and nucleotide sugar metabolism  hsa00520+2582  
Galactose metabolism  hsa00052+2582  
Metabolic pathways  hsa01100+2582  
According to Reactome, this protein belongs to the following pathway:
Galactose catabolism  REACT_532  
 
More information is available from:
Note 
Contrary to the human enzyme, the E.coli ortholog (AC P09147) does not catalyze the epimerization of UDP-N-acetylglucosamine to UDP-N-acetylgalactosamine. Compared to the E.coli enzyme, the sugar-binding pocket of the active site is 15% larger for the human enzyme, making it possible to accomodate the acetyl group.  
2
  • UniProtKB
 

Biophysicochemical properties

Kinetic parameters
KM 69 uM for UDP-galactose (at 37 degrees Celsius and pH 8.8)
Vmax 1.22 mmol/min/mg enzyme with UDP-galactose as substrate

Keywords

Biological process 
Carbohydrate metabolism  definition   [KW-0119]
Galactose metabolism  definition   [KW-0299]
Molecular function 
Isomerase  definition   [KW-0413]
Technical term 
Reference proteome  definition   [KW-1185]
 

Further external links

Enzyme and pathway databases
SABIO-RK: Q14376
Other
GenomeRNAi: 2582
PRO: PR:Q14376