1.14.13.128 native heteroxanthine demethylase partially 717407 1.14.13.128 Ni-NTA column chromatography 722538 1.14.13.128 Ni-NTA column chromatography and Sephacryl S200 gel filtration 727773 1.14.13.128 partial 707235 1.14.13.128 purification of two-subunit N-demethylase component (Ndm) of the N-demethylase holoenzyme 709854 1.14.13.128 recombinant His-tagged wild-type and mutant NdmC proteins by nickel affinity chromatography and gel filtration 765239