Sugar-1-kinase with a very high substrate specificity for the alpha-anomeric configuration of D-galacose (D-Gal). Converts also efficiently 2-deoxy-D-Gal to 2-deoxy-D-al-1-phosphate. alpha-D-galactose + ATP = ADP + alpha-D-galactose 1-phosphate + H(+) Magnesium. Can also use other divalent cations like manganese or calcium. Optimum pH is 7-8. Optimum temperature is 30-42 degrees Celsius. Carbohydrate metabolism; galactose metabolism. Expressed in roots, stems, leaves, flowers and young siliques. Higher expression in the elongating middle stem region than in the lower or upper stem region. Belongs to the GHMP kinase family. GalK subfamily.