Catalysis of the reaction: 3-methyl-5-hydroxy-6-(3-carboxy-3-oxopropenyl)-1H-2-pyridon + H2O = 2-oxobut-3-enanoate + 2,5,6-trihydroxy-3-methylpyridine.
3-methyl-5-hydroxy-6-(3-carboxy-3-oxopropenyl)-1H-2-pyridon hydratase-aldolase activity