5-hydroxy-6-methylpyridine-3,4-dicarboxylate + H(+) = 3-hydroxy-2-methylpyridine-5-carboxylate + CO2
5-hydroxy-6-methylpyridine-3,4-dicarboxylate + h(+) = 3-hydroxy-2-methylpyridine-5-carboxylate + co2