Oxidant & Antioxidant Balance Flashcards
Define and list examples of ROS
ROS: Reactive Oxygen Species - has unpaired electron, oxidising agent (gets reduced)
Hydroxyl (.OH)
Super oxide (O2-.)
Lipid Peroxyl (LOO-)
H2O2
Lipid Peroxide
Types of NOS
Nitrogen Oxygen Species = reactive nitrogenous species, unpaired e-
Peroxynitrite
Nitric Oxide
Nitric Dioxide
What is vasodilator than can also be NOS
Nitric Oxide
How does reactivity of species differ?
More reactive is if species involved in 1+ processes
How are ROS produced?
Reduction of O2 + e = O2.-
What is required to produce H2O2
O2-. (superoxide) + 2H+ + 2e- = H2O2
Why is mitochondria source of ROS
high O2 site = very prone to ROS production
Explain process of ROS production in Mitochondria
ATP production requires passage of E- across complexes inner mitochondrial membrane = causes H+ gradient
Which complex involved in mitochondrial ROS production
Complex I and III & G3P dehydrogenase
What type of ROS in mitochondria
Super oxide (O2-.)
What enzyme is involved in superoxide mitochondrial production
Glycerol-3-phosphate dehydrogenase: G3P Dehydrogenase
Why is complex III site of ROS
Complex III has binding site for QH2
QH2 is 2 step oxidation process which causes Q- unstable intermediate
Q- + O2 = O2*- (superoxide)
Why is Complex I a source of ROS?
Lack of O2 in tissue (i.e ischaemic stroke, blood vessel occlusion)
Increased succinate / metabolites in TCA
To continue TCA = succinate to fumurate causes E- backflow to Complex I
Reintroduction O2 = causes ROS
Explain how NO is a source for ROS
Nitric Oxide Synthase Nitric Oxide requires BH4 for vasodilation
