Involved in the degradation of glucose and galactose via the semi-phosphorylative Entner-Doudoroff pathway. Catalyzes the phosphorylation of 2-keto-3-deoxygluconate (KDG) and 2-keto-3-deoxygalactonate (KDGal) to produce 2-keto-3-deoxy-6-phosphogluconate (KDPG) and 2-keto-3-deoxy-6-phosphogalactonate (KDPGal), respectively. 2-dehydro-3-deoxy-D-gluconate + ATP = 2-dehydro-3-deoxy-6-phospho-D-gluconate + ADP + H(+) 2-dehydro-3-deoxy-D-galactonate + ATP = 2-dehydro-3-deoxy-6-phospho-D-galactonate + ADP + H(+) kcat is 3.8 sec(-1) for ATP, 5 sec(-1) for KDG and 5.4 sec(-1) for KDGal (at 60 degrees Celsius and pH 7.5). Optimum pH is between 7 and 8. Optimum temperature is between 70 and 80 degrees Celsius. Carbohydrate acid metabolism; 2-dehydro-3-deoxy-D-gluconate degradation; D-glyceraldehyde 3-phosphate and pyruvate from 2-dehydro-3-deoxy-D-gluconate: step 1/2. Homohexamer; trimer of dimers. Belongs to the carbohydrate kinase PfkB family.