Galactokinase 1 (GALK1)

Galactokinase catalyzes the phosphorylation of galactose to galactose-1-phosphate, the first step in galactose metabolism . The GALK1 promoter was found to have many features in common with other housekeeping genes, including high GC content, several copies of the binding site for the Sp1 transcription factor, and the absence of TATA-box and CCAAT-box motifs typically present in eukaryotic polymerase II promoters. Analysis by 5-prime-RACE PCR indicated that the GALK1 mRNA is heterogeneous at the 5-prime end, with transcription sites occurring at many locations between 21 and 61 bp upstream of the ATG start site of the coding region. In vitro translation experiments of the GALK1 cDNA indicated that the protein is cytosolic and not associated with endoplasmic reticulum membrane.