Reactome | B4GALT1:LALBA transfers Gal from UDP-Gal to Glc to form Lac

B4GALT1:LALBA transfers Gal from UDP-Gal to Glc to form Lac

Stable Identifier

R-HSA-5653878

Type

Reaction [transition]

Species

Homo sapiens

Compartment

Golgi lumen, Golgi membrane

Synonyms

UDP-alpha-D-galactose + D-glucose => lactose + UDP + H(+), Glc + UDP-Gal => Lac + UDP

ReviewStatus

5/5

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B4GALT1:LALBA transfers Gal from UDP-Gal to Glc to form Lac

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In the Golgi membrane, the B4GALT1 subunit of the B4GALT1:LALBA (beta-1,4-galactosyltransferase 1 : alpha-lactalbumin) complex catalyzes the transfer of galactose from UDP-galactose to free glucose to form galactose and UDP (Andrews 1970; Ramakrishnan & Qasba 2001). The representation here of a stable protein complex catalyzing the transformation of small molecule substrates provides a simplified view of the true reaction mechanism (Brew and Hill 1975), but is sufficient to identify the key participating molecules and their roles.

Literature References

PubMed ID	Title	Journal	Year
11947697	Purification of lactose synthetase a protein from human milk and demonstration of its interaction with alpha-lactalbumin Andrews, P	FEBS Lett.	1970
806951	Lactose biosynthesis Brew, K, Hill, RL	Rev. Physiol. Biochem. Pharmacol.	1975
11419947	Crystal structure of lactose synthase reveals a large conformational change in its catalytic component, the beta1,4-galactosyltransferase-I Ramakrishnan, B, Qasba, PK	J. Mol. Biol.	2001