BARLEY OXALATE OXIDASE IS A HEXAMERIC PROTEIN RELATED TO SEED STORAGEPROTEINS - EVIDENCE FROM X-RAY CRYSTALLOGRAPHY

The oxalate oxidase enzyme expressed in barley roots is a thermostable , protease-resistant enzyme that generates H2O2. It has great medical importance because of its use to assay plasma and urinary oxalate, and it has also been used to generate transgenic, pathogen-resistant crop s. This protein has now been purified and three types of crystals grow n. X-ray analysis shows that the symmetry present in these crystals is consistent with a hexameric arrangement of subunits, probably a trime r of dimers. This structure may be similar to that found in the relate d seed storage proteins. (C) 1998 Federation of European Biochemical S ocieties.