Purification and Properties of Oxalate Oxidase from NaCl Stressed Grain Sorghum Seedlings

The effect of NaCl stress on molecular and biochemical properties of oxalate oxidase (OXO) was studied in leaves of grain sorghum hybrid (var CSH-14) seedlings. There was no effect on molecular weight and number of subunits of the enzyme but it showed some important changes in its kinetic parameters such as Km for oxalate and Vmax. Optimum pH (5.8), activation energy (5.084 kcal mole−1), time of incubation (6 min) and Km for oxalate (1.21×10t-4M) were increased, while Vmax (0.182 mmole min−1) decreased and no change in optimum temperature was observed. This showed that substrate affinity and maximum activity of the enzyme was adversely affected. The specific activity of oxalate oxidase was increased in seedlings grown in a NaCl containing medium compared to normal, which reveals the increased de novo synthesis of the enzyme to sustain oxalate degradation.