Vitamin C Flashcards
What is the active form of Vitamin C
Ascorbic acid
What reaction does ascorbic acid undergo
oxidation (electron donor)
What is formed after oxidation of ascorbic acid
Ascorbyl radical (free radical)
What reaction does ascorbyl radical undergo
oxidation (electron donor)
What is formed after oxidation of ascorbyl radical
dehydroascorbic acid (stable, inactive)
What reaction does dehydroascorbic acid undergo
Reduction
What is formed after reduction of dehydroascorbic acid
Ascorbic acid
What enzyme system reduces dehydroascorbic acid
Glucathione perioxidase
What is a structural element of the glucathione perioxidase system
Selenium
How is vitamin C digested
No digestion!
What are non-citrus sources of vitamin C
cantaloupe, kiwi, mango, watermelon, broccoli, peppers, brussel sprouts
What is the RDA for vitamin C
75mg/day women; 90mg/day men
How is vitamin C absorbed
Saturable transporter; diffusion at high concentration
What is the absorption % of vitamin C
75-90%; at high rates of consumption, absorption decreases
How is vitamin C transported in blood
free form (water-soluble/no transporter)
Does absorption of vitamin C into cells require a transporter
Yes
At what amount will blood level saturate
150-200mg
What happens to vitamin C once blood level saturation occurs
Excreted in urine
What is the vitamin C saturation point for WBCs
100mg
What is a potential function for a high dose of vitamin C
pro-oxidant, isolate to kill cancer cells
Vitamin C is an electron donor for what
8 mammalian enzymes
What is the function of monooxygenase
Insert Oxygen
In what processes are monooxygenases involved
Neurotransmitter synthesis(1 enzyme), peptide hormones and post-translational modification(1)
What neurotransmitters are synthesized using monooxygenase
Serotonin, norepinephrine, hormones
