Catalyzes the hydrolitical oxidation of 1,3,7-trimethylxanthine (caffeine) by incorporation of an oxygen atom originating from a water molecule into position C-8 to produce 1,3,7-trimethyluric acid (TMU). Coenzyme Q0 is the preferred electron acceptor and coenzyme Q2 can also be used, but oxygen and NADP cannot. a ubiquinone + caffeine + H2O = 1,3,7-trimethylurate + a ubiquinol kcat is 10 min(-1) with caffeine as substrate. Optimum pH is 70. 30-min incubation at 70 degrees Celsius drastically reduces the enzyme activity to 11% of the initial value, and 77% of the activity remains after 30 min of incubation at 42 degrees Celsius. Heterotrimer composed of an alpha (CdhA), a beta (CdhB) and a gamma (CdhC) subunit.