Involved in the degradation of glucose via the Entner-Doudoroff pathway. Catalyzes the reversible cleavage of 2-keto-3-deoxy-6-phosphogluconate (KDPG) and 2-keto-3-deoxygluconate (KDG) forming pyruvate and glyceraldehyde 3-phosphate or glyceraldehyde, respectively. It is also able to catalyze the reversible cleavage of 2-keto-3-deoxy-6-phosphogalactonate (KDPGal) and 2-keto-3-deoxygalactonate (KDGal). It is equally active with both D- and L-glyceraldehyde. 2-dehydro-3-deoxy-6-phospho-D-gluconate = D-glyceraldehyde 3-phosphate + pyruvate 2-dehydro-3-deoxy-D-gluconate = D-glyceraldehyde + pyruvate 2-dehydro-3-deoxy-6-phospho-D-galactonate = D-glyceraldehyde 3-phosphate + pyruvate 2-dehydro-3-deoxy-D-galactonate = D-glyceraldehyde + pyruvate Optimum pH is 5.5, and 50% of activity is found at pH 4.5 and 7.5. Optimum temperature is 65 degrees Celsius. It shows high thermostability. At 70 degrees Celsius, the enzyme does not lose activity upon incubation for 2 hours. The half-lives of the enzyme at 80 degrees Celsius and 90 degrees Celsius are 20 minutes and 15 minutes, respectively. Carbohydrate acid metabolism; 2-dehydro-3-deoxy-D-gluconate degradation; D-glyceraldehyde 3-phosphate and pyruvate from 2-dehydro-3-deoxy-D-gluconate: step 2/2. Homotetramer; dimer of dimers. Belongs to the DapA family. KDPG aldolase subfamily.