Involved in the degradation of galactose via the DeLey-Doudoroff pathway. 2-dehydro-3-deoxy-D-galactonate + ATP = 2-dehydro-3-deoxy-6-phospho-D-galactonate + ADP + H(+) Carbohydrate acid metabolism; D-galactonate degradation; D-glyceraldehyde 3-phosphate and pyruvate from D-galactonate: step 2/3. Cells lacking this gene fail to grow on galactose as sole carbon source. Belongs to the DgoK family.