InterPro domain: IPR000705

Galactokinase catalyses the first reaction in the galactose metabolism pathway, the ATP-dependent phosphorylation of galactose, yielding galactose-1-phosphate [ 1 , 2 ].Deficiency in this enzyme results in the disease galactosemia, which is responsible for theformation of cataracts in newborn babies, and is possibly responsible for presenile cataracts inadults [ 3 ]. In yeast, the GAL3 gene product is required for the GAL4-mediated inductionof other enzymes involved in galactose metabolism. The induction of GAL1 production then reinforcesthis process, increasing the expression of other galactose-inducible genes. GAL3 has been shown tobe similar to the GAL1 protein [ 3 ].

1. Yeast regulatory gene GAL3: carbon regulation; UASGal elements in common with GAL1, GAL2, GAL7, GAL10, GAL80, and MEL1; encoded protein strikingly similar to yeast and Escherichia coli galactokinases. Mol. Cell. Biol. 8, 3439-47
2. Cloning of a human galactokinase gene (GK2) on chromosome 15 by complementation in yeast. Proc. Natl. Acad. Sci. U.S.A. 89, 10887-91