The structure of p-nitrocatechol sulfate dipotassium salt dihydrate (dipota
ssium 2-oxido-5-nitrophenyl sulfate dihydrate), K-2(C6H3NO7S). 2H(2)O, is r
eported. An accurate structural determination was needed to derive reliable
restraints for use in macromolecular refinement at medium resolution of a
protein-substrate complex.