1.4.3.19 the isolated apoprotein species is present in solution as a monomer which rapidly recovers its tertiary structure and converts into the tetrameric holoenzyme following incubation with free FAD. The reconstitution process follows a particular two-stage process, the spectral properties of the reconstituted holoenzyme are virtually indistinguishable from those observed with native glycine oxidase, while the activity is only recovered to about 50%. The urea-induced unfolding process of glycine oxidase can be considered as a two-step process. Only a single transition at 4.5 M urea concentration is observed for the apoprotein form. The chemical denaturation of glycine oxidase holoenzyme is partially reversible 696489