Catalyzes the conversion of 2,6-dihydroxypyridine into 2,3,6-trihydroxypyridine in the nicotine degradation pathway. 2,6-dihydroxypyridine + H(+) + NADH + O2 = 2,3,6-trihydroxypyridine + H2O + NAD(+) Optimum pH is 8.0. Optimum temperature is 20 degrees Celsius. Alkaloid degradation; nicotine degradation. Homodimer.