Abstract
The measurement of purine nucleosides and bases in biological fluids is a particularly challenging problem because their concentrations are extremely low and very limited amount of the specimen is often available (e.g. paediatric specimens). Abnormal levels of these compounds are associated with inborn errors of purine metabolism, neoplastic diseases and conditions leading to a net ATP degradation. Xanthine oxidase-initiated isoluminol chemiluminescence, in the absence of peroxidase, has been employed in our laboratories for the assay of hypoxanthine/xanthine, guanine, guanosine, inosine and adenosine. Any purines lower in the catabolic sequence than that to be assayed are removed by a preincubation in the presence of appropriate enzymes. The assayed purine is converted to xanthine and/or hypoxanthine. Isoluminol chemiluminescence elicited by xanthine oxidase/hypoxanthine-xanthine system, is enhanced by adding p-iodophenol to the reaction mixture. The assay is rapid, specific, sensitive (1 nmol/liter) and suitable for the assay of purines in deproteinized biological fluids, provided that uric acid is removed by preincubation with uricase and that EDTA is added to the reaction mixture. Internal standardization is required. A very sensitive luminometric assay for the determination of xanthine oxidase activity in biological samples is also described.
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Siacomella, A., Salerno, C., Cardelli, P. et al. 42 CHEMILUMINESCENT ASSAYS IN THE STUDY OF PURINE METABOLISM. Pediatr Res 24, 118 (1988). https://doi.org/10.1203/00006450-198807000-00066
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DOI: https://doi.org/10.1203/00006450-198807000-00066