Defective GALT does not transfer UMP to Gal1P

Stable Identifier
Reaction [transition]
Homo sapiens
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Galactose-1-phosphate uridylyltransferase (GALT) is one of the enzymes involved in galactose metabolism in the Leloir pathway. GALT catalyses the transfer of uridine monophosphate (UMP) from UDP-glucose (UDP-Glc) to galactose-1-phosphate (Gal1P) to form UDP-galactose (UDP-Gal). Defects in GALT can cause Galactosemia (GALCT; MIM:230400), an autosomal recessive disorder of galactose metabolism presenting in neonatals that causes jaundice, cataracts, and mental retardation. Q188R, K285N are the most common mutations in US Caucasians (Reichardt et al. 1991, Elsas et al. 1994). S135L is the most common mutation of the American black population (Lai et al. 1996). Protein misfolding is likely to be the underlying molecular cause in the majority of cases (McCorvie et al. 2013).
Literature References
PubMed ID Title Journal Year
8198125 A common mutation associated with the Duarte galactosemia allele

Dembure, PP, Fridovich-Keil, J, Elsas, LJ, Paulk, EM, Langley, S, Hjelm, LN

Am. J. Hum. Genet. 1994
1897530 Molecular characterization of two galactosemia mutations: correlation of mutations with highly conserved domains in galactose-1-phosphate uridyl transferase

Woo, SL, Reichardt, JK, Packman, S

Am J Hum Genet 1991
23583749 Misfolding of galactose 1-phosphate uridylyltransferase can result in type I galactosemia

McCorvie, TJ, Fridovich-Keil, JL, Gleason, TJ, Timson, DJ

Biochim. Biophys. Acta 2013
8551426 A prevalent mutation for galactosemia among black Americans

Dembure, PP, Singh, RH, Elsas, LJ, Lai, K, Langley, SD, Hjelm, LN

J. Pediatr. 1996
Catalyst Activity

UDP-glucose:hexose-1-phosphate uridylyltransferase activity of GALT mutants [cytosol]

Normal reaction
Functional status

Loss of function of GALT mutants [cytosol]

Name Identifier Synonyms
galactosemia DOID:9870 Galactose intolerance, Galactosaemia
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