[A new method for the determination of xanthine oxidase activity by high-performance liquid chromatography with...

A non-radiochemically sensitive method for the determination of xanthine oxidase (XO, EC 1.1. 3.22) activity is devised. We have enabled to detect the low activity of XO in human serum or peripheral lymphocyte lysates by the pretreatment of samples with activated charcoal, and by the employment of a sensitive high-performance liquid chromatography with electrochemical detection. This method was shown to be reliable and reproducible, and allowed us to evaluate XO activity in various clinical samples. XO activity in serum, but not in peripheral lymphocytes reflected the degree of liver damage. No relationship was found between serum XO activity and serum uric acid. No XO activity was detected in sera from patients with hereditary xanthinuria. These results suggested this method to be quite useful for rapid diagnosis of the patients with abnormal purine metabolism, especially in that with hereditary xanthinuria.