1. Friendship University of Russia, Moscow, Russia 2. Research Center of Neurology, Russian Academy of Medical Sciences, Moscow, Russia 3. Research Center of Neurology, Russian Academy of Medical Sciences, Moscow, Russia; Institute of Biomedical Chemistry, Moscow, Russia 4. G.K. Scryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Рushchino, Russia 5. Friendship University of Russia, Moscow, Russia; Institute of Biomedical Chemistry, Moscow, Russia
Abstract: L-Amino acid oxidases (L-ААО, EC 18.104.22.168) comprise a group of flavoproteins, catalyzing oxidative deamination of L-alpha amino acids to the corresponding alpha-keto acids, NH3 and Н2О2. In most cases these enzymes present homodimeric molecules with a molecular mass of 100-150 kDa, which were shown to possess antiviral, antifungal and antitumor activity. L-lysine alpha-oxidase (LO) holds an outstanding place among this group of enzymes and its biological role may differ significantly from the other L-AAO, because it cleaves an essential amino acid – L-lysine without significant action on the other amino acids. Although much research has examined LO effects in the organism, the molecular basis of these effects is yet to be identified. To fill this gap, the present work addressed one of hypothetical mechanisms of LO biological action using the enzyme from Trichoderma cf. aureoviride Rifai ВКМF-4268D and rat pheochromocytoma PC-12 as a model cell line. Using flow cytometry a dose-dependent cytotoxicity of LO was shown. The significant growth of intracellular reactive oxygen species levels, detected by 2,7-dichlorodihydrofluorescein assay, implies generation of peroxide as one of the molecular mechanisms of LO cytotoxic action, although this does not rule out other probable ways of LO action in the organizm.