Partitioning of reactive oxygen species via the re-oxidation of electron transfer flavoprotein

Abstract

The biology of Reactive Oxygen Species are poorly understood. Within a healthy cell, Reactive Oxygen Species behave as signaling molecules, although overproduction leads to oxidative damage. In order to understand when the overproduction of Reactive Oxygen Species takes place, or leads to oxidative damage, the elementary step of quantification becomes necessary. Electron Transfer Flavoprotein is a known Reactive Oxygen Species producing enzyme and was studied. Electron Transfer Flavoprotein is a key-player within the production of energy within the eukaryotic mitochondria. The redox nature of Electron Transfer Flavoprotein's catalytic cofactor, flavin adenine dinucleotide produced two types of ROS; the superoxide anion (O 2 °-) and hydrogen peroxide (H 2 O 2). Electron Transfer Flavoprotein produced roughly five-fold more O 2 °-compared to H 2 O 2 as the enzyme became oxidized. It has been put forward that the production of these two Reactive Oxygen Species is dictated by the formation of a radical pair between the flavin adenine dinucleotide of Electron Transfer Flavoprotein and molecular oxygen. Two types of radical pairs can be formed, either in a triplet or singlet state, and the rate in which these states occur can be influenced by a static magnetic field. Therefore, the effect of a magnetic field on these products was also studied. Upon the suppression of magnetic field strength, the production of H 2 O 2 decreased and a proportional increase of O 2 °-was observed.