1. LEE, R.T., PETERSON, C.L., CALMAN, A.F., HERSKOWITZ, I.
AND O'DONNELL, J.J.
Cloning of a human galactokinase gene (GK2) on chromosome 15 by
complementation in yeast.
PROC.NATL.ACAD.SCI.U.S.A. 89 10887-10891 (1992).
2. BAJWA, W., TORCHIA, T.E. AND HOPPER, J.E.
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 3439-3447 (1988).
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 the formation of cataracts
in newborn babies, and is possibly responsible for presenile cataracts in
In yeast, the GAL3 gene product is required for the GAL4-mediated induction
of other enzymes involved in galactose metabolism . The induction of
GAL1 production then reinforces this process, increasing the expression of
other galactose-inducible genes . GAL3 has been shown to be similar to
the GAL1 protein .
GALCTOKINASE is a 4-element fingerprint that provides a signature for the
galactokinase family. The fingerprint was derived from an initial alignment
of 6 sequences: the motifs were drawn mainly from the N-terminal portion of
the alignment, motif 1 including the region encoded by PROSITE pattern
GALACTOKINASE (PS00106), and motif 3 encoding a possible ATP-binding site.
Two iterations on OWL27.0 were required to reach convergence, at which point
a true set comprising 15 sequences was identified. Two partial matches were
also found: KLGAL is a galactokinase fragment; and S78870 is a galactokinase
from Streptococcus thermophilus F410 that fails to match motif 1.
An update on SPTR37_10f identified a true set of 20 sequences, and 5