Quantification of Urinary Oxalate with Alkylamine Glass Bound Amaranthus Leaf Oxalate Oxidase

ABSTRACT

A method has been developed for discrete analysis of urinary oxalate employing alkylamine glass bound oxalate oxidase partially purified from mature leaves of Amaranthus spinosus. In the method H₂O₂ is generated from urinary oxalate by immobilized oxalate oxidase, which is measured by a colour reagent containing 4-aminophenazone, phenol and horseradish peroxidase in phosphate buffer, pH 7.0. The chromogen formed is read at 520nm. The minimum detection limit of the method is 0.9mg/L. The analytical recovery of added oxalate in urine was 98.0±2.7% (mean±SD). Within batch and between batch CV's were less than 4% and 3%, respectively, for urinary oxalate determination. The mean value of urinary oxalate measured by the present method is comparable to that obtained by the Sigma kit method (r=0.98).

Keywords::

• Oxalate
• Oxalate oxidase
• Peroxidase
• Amaranthus spinosus
• Horseradish
• Urine
• Immobilization
• Alkylamine glass