Reactive Oxygen Species Flashcards
Hypoxia inducing factor (HIF) is a_________in response to hypoxia
Transcriptional regulator
HIF under normal conditions is recognized by the enzyme________which hydroxylate it which are then recognized by_______that ubiquinates it for degradation
PHD (Prolyl hydroxylase);VHL
Under hypoxia conditions, HIF -1 alpha and HIF-1 beta bind to________on the DNA as a transcription factor to drive the expression of genes for_______
HRE (Hypoxia response element); glycolysis, increase RBC’s
Mitochondrial diseases derive from the________of the ETC
Overuse
Overuse of the electron transport chain causes a leakage of________which increases the likelihood of producing ROS
Electrons
Oxidative phosphorylation disorders can derive from____________which are responsible for building the ETC
mutations in mitochondrial genome
ROS’s have what kind of effect on mitochondria
Decrease ATP and electrochemical potential
Lactic acid build up
Mitochondrial disorder effect what kinds of cells
Cells which require high ATP
Name the common free radicals
Superoxide
Hydroxyl radical
Superoxide formed by
adding 1 electron to O2
Hydrogen peroxide is formed by
Adding 1 electron and 2 protons to superoxide
An unavoidable byproduct of the ETC is
Superoxide
_________is a major site of ROS production
Mitochondria
Reacting hydrogen peroxide with an H ion and an electron forms the radical
Hydroxyl
Superoxide is mainly generated in which sites of the ETC
Complex 1 and 3
Peroxisomes are a sight for which ROS during fatty acid oxidation? How are they formed?
Hydrogen peroxide; transfer of electrons from FADH2 to O2
This family of enzymes catalyzes the transfer of electrons from NADPH to O2 to form superoxide
NADPH oxidase
NADPH oxidases are found in________ and produce ROS to kill engulfed microbes within the cell
Membranes of phagolysosomes in immune cells
The enzyme_______catalyzes the formation of________from_______which then attacks bacteria
Myeloperoxidase; HOCL (Hypochlorus acid); hydrogen peroxide and Cl
ROS can effect DNA by
Alterating nucleotide bases
Break the depxyribose backbone
Programmed cell death if DNA cannot be prepared
ROS can effect Lipids by
Lipid peroxidation which changes membrane viscosity,
increasing membrane permeability for calcium
Increasing membrane permeability to increase swelling
ROS can effect proteins by
Amino acid conversions
Cleavage of peptide bonds
This enzyme is the primary defence against ROS which converts superoxide to hydrogen peroxide and O2
Superoxide dismutase
The gene encodes for superoxide dismutase
SOD1
Superoxide dismutase is found in
Mitochondria, cytosol, and extracellularly
This enzyme promotes the reaction of converting H2O2 to water and O2
Catalase
Catalases are found in_______and are high yield in the kidney and liver
Peroxisomes
Catalases protect the cell from
Respiratory burst
This enzyme exists as a family of selenium enzymes and are the means for converting H2O2 outside of peroxisomes
Glutathione
__________is essential for protection against free radical injury and is provided by the penthouse phosphate pathway
NADPH
GSH is oxidized to form GSSG which turns H2O2 into H2O using________as the enzyme
Glutathione peroxidase
This enzyme in the pentode phosphate pathway maintains a high NADPH ratio and is the rate limiting step for the pentode phosphate pathway
G6PDH (glucose-6-phosphate-dehydrogenase)
G6PDH is inhibited by_____ and activated by_____
NADPH; NADP
Nrf2 is a______which activates the antioxidant response element
Transcription factor
Antioxidant response element (ARE) dependent enzymes include
Catalase and superoxide dismutase
Nrf2 is bound to an inactive form when bound to________which directs ubiquitination of Nrf2 under normal conditions
Keap1
Nrf2 is activated under________by dissociation of Keap1
Oxidative stress
