Free Radicals and Antioxidants Flashcards
propertoes of oxygen in ground state
can absorb energy from light, porphyrins or other sources and get to the exicted state
how is superoxide anion generated
one electron reduction of molecular oxygen, usually invovling a metalb catalyst
how is hydrogen peroxide generated
transfer of 2 electrons
how is hydroxyl radical generates
transfer of 3 electrons.
which of the oxygen radicals is the most reactive
hydroxyl radical
how do you get reactive oxygen from ETC
quinone in complex III gets oxidized to form superoxide anion
how do you get reactice oxyen from NADPH/cytochrome oxidases
if second transfer of electrons fails, superoxide anion is released from enzyme
chronic alcohol consumption stresses the liver in what 2 ways
oxidative stress from hydrogen peroxide
DNA damage
what reactive oxygen does the xanthine oxidase reaction produce
hydrogen peroxide
how are iron and copper involved in free radicals
free iron and copper irons can donate an electron to molecular oxygen or hydrogen peroxide
what is iron boudn to
ferritin and transferrin
what is copper bound to
ceruloplasmin
what causes hereditary hemochromatosis
mutation in HFE gene
symptoms of hereditary hemochromtosis
destruction of liver, pancreaus, and heart muscle cells
where is superoxide dismutase (SOD) exxpressed
cytoplasm and mitochondria
SOD function
convert superoxided into hydroen perodxide
catalase
heme containing enzyme that detoxes hydrogen perdoixe
glutathione peroxidase
uses electrons to reudce hydrogen peroxide
ascorbic acid
water soluble electron donor to free radicals
vitamine E
lipi solube radical scapventure
waht does vit E protect against
damage from free radicals as well as from lipid peroxidation
how does vit A reduce oxidative damage to membranes
electron donor for reduction of radicals
quenches vibration energy of singlet oxygen
GSH
has thiol group that can donate elctron to radical, becomes oxidized
how is GSSG reduceed back to GSH
glutathione reductase
polyphenols
water soluble antioxidants that are in plant extracts
where do most electrons originate from
NADPH
how does glutathione peroxidase help fight radical damage in RHCs
destroy hydrogen and organic peroxides
how does SOD help fight radical damage in RBCS
destroy superoxide
how does catalase right radical damage in RBCs
convert hydrogen peroxide
what in RBCs directly reacts with ROS
RSH, vit C, vit E
how does methemoglobin help fight radical damage in RBCs
methemoglobin reductase reparis oxidative damage by reducing iron, convert methemoglboin back to hemoglobin
when is oxidative stress present
when conc of ROS exceeds cell capcity for detox
what is oxidative stress daaming to
lipids, DNA, proteins
the most serious damage by hydroxyl radical to membrans is what
peroxidation of polyunsaturated fatty acids
process of lipid peroxidation
1) hydroxyl radical takes electron from PUFA, produces lipid radical
2) lipid radical react with oxygen to form lipid peroxides
3) liipd peroixes are unstable and take elctrons
what is a good marker for oxidative stress
plasma malondialedhyde conc
how does hydroxyl radical fuck up DNA
produces DNA double stranded breaks
what forms peroxynitirite
superoxide and peroxynitrate anions
