The enzyme, characterized from the bacterium Pseudomonas sp. CBB1, is part of the bacterial C-8 oxidation-based caffeine degradation pathway. The product decomposes spontaneously to a racemic mixture of 3,6,8-trimethylallantoin. The enzyme shows no acitivity with urate. cf. EC 1.14.13.113, FAD-dependent urate hydroxylase.