Sequence comparison of GALDH and related VAO members. Top section, Schematic representation of the primary structure of mature GALDH with the FAD-binding domain in blue and the cap domain in red. Bottom section, Sequence alignment around the conserved Cys. The accession numbers used are as follows: Arabidopsis GALDH (AtGALDH), Q8GY16; Brassica oleracea GALDH (BoGALDH), O47881; Ipomoea batatas GALDH (IbGALDH), Q9ZWJ1; Rattus norvegicus l-gulono-1,4-lactone oxidase (RnGUO), P10867; Trypanosoma cruzi galactonolactone oxidase (TcGAL), Q4DPZ5; Saccharomyces cerevisiae d-arabinono-1,4-lactone oxidase (ScALO), P54783; P. griseoroseum d-gluconolactone oxidase (PgGLO), Q671X8; alditol oxidase (AldO), Q9ZBU1; xylitol oxidase (XylO), Q9KX73; and sorbitol oxidase (SorbO), P7011. Similar residues are shaded in gray. The conserved Cys is indicated in orange, and conserved residues lining the active site entrance in AldO are marked in red.