Catalyzes the dehydration of D-xylonate to 2-dehydro-3-deoxy-D-arabinonate during D-xylose degradation. Can also dehydrate D-gluconate, with similar catalytic efficiency. Has weak activity with D-galactonate, D-fuconate and L-arabinonate. D-xylonate = 2-dehydro-3-deoxy-D-arabinonate + H2O D-gluconate = 2-dehydro-3-deoxy-D-gluconate + H2O kcat is 1406 min(-1) with D-xylonate as substrate. kcat is 2626 min(-1) with D-gluconate as substrate. kcat is 46 min(-1) with L-arabinonate as substrate. kcat is 218 min(-1) with D-galactonate as substrate. kcat is 196 min(-1) with D-fuconate as substrate. Optimum pH is 8.5. Carbohydrate metabolism; D-xylose degradation. Homotetramer. Deletion mutant cannot grow with D-xylose as the sole carbon source. Belongs to the IlvD/Edd family.