purine metabolic pathway purine degradation pathway 2011-06-06T04:49:30Z PW:0000866 Purine catabolism Those enzymatic reactions involved in the degradation pathway of purines. Several enzymes are involved in the breakdown of adenine and guanine to uric acid. Primates, birds and other animal excrete uric acid. In other species uric acid is further metabolized to allantoin. pathway purine nucleobase catabolic process vpetri