[Photosensitized oxidation of asparagine-glutamine deamidase from Pseudomonas fluorescens]

The process of oxidation of deamidase of asparagine-glutamine from Pseudomonas fluorescens sensitized with dyes has been studied. Oxidation brings about complete inactivation of the enzyme which, however, retains the quaternary structure. In the course of photooxidation, tryptophan residues are first destroyed and then those of histidine. Possibilities of the participation of these amino acid residues in catalysis and maintenance of active conformation of the enzyme are discussed.