Exam - Reactive Oxygen Species and Vitamin E Flashcards
how are reactive oxygen species produced
as a by-product of the ETC when proper electron flow fails (leakage)
where do reactive oxygen species occur
oxygen rich environments where oxygen can react with electrons
what do radicals have
unpaired electrons
what can radicals caused
mutations in SOD which cause ALS
what does H2O2 get converted to H2O by
glutathione peroxidase and catalase
supplement label on vitamin E
mixed tocopherol antioxidant support
what is vitamin E a general term for
8 structurally-related compounds (vitamers)
what are the 8 vitamers grouped into
4 tocopherols
4 tocotrienols
difference between tocopherols and tocotrienols
tocopherols - saturated side chains with 16 carbons
tocotrienols - unsaturated side chains with 16 carbons
which vitamer is the only one with significant activity in the body
alpha-tocopherol
where are the vitamers found
naturally in food
what is the antioxidant site on alpha-tocopherol
the hydroxyl group
what does the alpha isoform contain more of
most methylated ring
what configuration is natural alpha-tocopherol
RRR - fits into binding pocket of the tocopherol transport protein
do tocopherols or tocotrienols have lower levels in food
tocotrienols
where do tocotrienols have antioxidant activity
liver only - that’s where they stay
food sources of vitamin E
nuts, seeds, vegetable oils, avocado - sensitive to preparation
where is vitamin E stored in animals
adipose
what is vitamin E RDA based on
only alpha-tocopherol
while vitamin E deficiencies are rare, where can they occur
pre-mature infants
people with fat malabsorption disorders/gallbladders removed
people with genetic defect in lipoproteins or TTP
what are vitamins E deficient pre-mature infants at risk for
hemolytic anemia because they are kept in oxygen rich incubators
what fraction of vitamin E radical is excreted as quinone through urine
1/3
what fraction of vitamin E radical is excreted as vitamin E dimer through bile
2/3
