Abstract
In the determination of uric acid we investigated the interference of ascorbic acid on the uricase-peroxidase reaction, and studied the elimination of its interference with use of ascorbate oxidase. The investigation was conducted in comparison with the uricase-catalase method described by Kageyama.
1) Interference exerted by one mole of ascorbic acid on the uricase-peroxidase (MBTH-DMA) reaction was correspondent to about one mole reduction of uric acid value.
2) 0.5U/ml of ascorbate oxidase in the uricase solution (pH 7.2) was enough to break down ascorbic acid up to 17mg/dl in the samples within 2.5min at 37°C.
3) In the case of urine samples including patients, the addition of ascorbate oxidase gave the almost concordant values of uric acid with those obtained by the catalase method.
4) In the case of serum samples, there remained significant discrepancies in uric acid values from those of the catalase method, although ascorbic acid was removed by ascorbate oxidase. The discrepancies were revealed as the kind of proportional bias both in normal adults and patients, and in the latter there were some non-icteric sera indicating furthermore considerable discrepancies.
