The enzyme uricase, also known as urate oxidase, converts uric acid into allantoin in most mammals
In humans, the uricase enzyme is nonfunctional due to a frameshift mutation that occurred during evolution. This means that uric acid, a weak acid that is relatively insoluble, is the end product of purine metabolism in humans.
High blood uric acid levels are associated with a number of health issues, including gout, cardiovascular disease, and diabetes. Low urate levels, on the other hand, may increase the risk of neurodegenerative diseases.