Oxalate oxidase known to catalyse the aerobic oxidation of
oxalic acid into CO2 and H2O2, has been found in bacteria, fungi, mosses and some higher plants. So far, a membrane bound
oxalate oxidase from Pseudomonas sp. OX-53 and a soluble
oxalate oxidase from seedling plants of barley and grain sorghum has been purified to homogeneity by conventional purification methods. The
enzyme has been immobilized onto insoluble support such as
nylon tubing,
zirconia coated alkylamine glass,
polyamide membrane, CO2 gas sensing
electrode, H2O2 sensor probe and polyanionic
electrolyte such as ethylaminemaleic
anhydride (EMA). Compared to free
enzyme the
immobilized enzyme showed an increase in optimum pH, decrease in Vmax and time for maximum activity, higher resistance to inhibition by NaCl but no change in Km value. The
immobilized enzyme has been used in both continuous flow system and discrete assays and in
enzyme electrode for determination of
oxalate in urine, blood and food stuff, which is essentially required for the diagnosis and treatment of
hyperoxaluria and
calcium oxalate urinary stones. The degradation of endogenous
oxalate in rat by immobilized
oxalate oxidase has opened a new vistas in
enzyme therapy of
hyperoxaluria.