oxidative stress Flashcards
what is oxidative stress
imbalance between reactive oxygen species and a bio systems ability to manage them
what are free radicals
molecules with an unpaired electron
what are two free radical species
super oxide and hydrogen peroxide
where do cellular ros come from
byproducts of chemical reacions
also used by enzymes to kill microbes
where are ros found in the immune system
found in phagocytic cells such as macrophages and neutrophils
are also found around the edge of wound cells to trigger immune response
whats the redox of cells
cells are highly reducing environment, possibly due to cells evolving when oxygen is scarcer
where are free radicals produced in the mitochondrial process
if electrons leak from the mitochondrion, different ros can be generated, depending on how many electrons leak
0.2% of oxygen consumption is converted to ros
which enzyme is used to generate reactive oxygen species
nadph oxidase
what damage do ros do to bioproducts
lipids and proteins must be resythesised, DNA is mostly repaired but any damage is permanent
10000 events a day, mostly repaired
what protiens are at risk of ros
those with reactive cystine and methionine residues, some are reversible, however if one gets ecidised twice then changes are irreversible
what diseases are associated with oxidative damage(not CVD)
neurodegenerative diseases
muscular dystrophy
rheumatoid arthritis
cataracts
what are some exogenous souces
uv exposure
radiation
air pollution
heavy metals
smoke
what are antioxidants and how do they work
they are the opposite of ros and they have a donor electron to donate to the free radical
they are in 2 classes
what are the 2 classes of antioxidant and what are some examples
enzymatic catalase
and
non enzymatic vitamin e
what are two important antioxidants
vitamin e is lipid soluble and used to defend membranes form damage
glutathiponine is very important, its glutamate, cysteine and glycine as a redox buffer, acts to take the punches for the rest of the cell
also anthocyanins
