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What are purine derivatives?

The term "purine derivatives (PD)" refers to allantoin, uric acid, xanthine and hypoxanthine collectively. These are the degradation products from purines, purine bases and purine nucleosides.

In ruminants, hypoxanthine and xanthine are converted to uric acid by xanthine oxidase, and uric acid is further converted to allantoin by uricase. The presence of high activities of xanthine oxidase in cattle and buffalo plasma leads to the complete conversion of hypoxanthine and xanthine to uric acid before excretion in the urine.

All four compounds are excreted in the urine of sheep, goat, llamas, red deer and camels; but xanthine and hypoxanthine are virtually absent from urine of cattle, buffaloes and yaks.

Click here to view the composition of PD in different animals


Name Hypoxanthine
Uric acid





Molecular weight 136 152 168 158
pK 2.0;8.9;12.1 7.4;11.1 5.4;11.3 8.9