Vitamin C Flashcards
1
Q
Hippocrates
A
describe
symptoms of scurvy.
2
Q
Lind
A
prescribes
oranges and lemons as cure
3
Q
Holst and Frohlich
A
scurvy accidentally
produced in guinea pigs (can’t
produce it themselves).
4
Q
Gyorgyi
A
identifies factor as “hexuronic
acid” a reducing agent.
5
Q
circulating form
A
ascorbate (ascorbic
acid). Water soluble, no transporter.
6
Q
uptake
A
Taken up by
SVCT-1 & SVCT-2 in most tissues.
7
Q
excretion
A
Intakes >500mg, all vitamin C is
excreted in urine as DHAA or
metabolites
8
Q
Collagen synthesis
A
structural protein found in skin, bones, tendons and cartilage; 1/3 of total protein in body. Enzymes: Proly 3-hydroxylase, proly 4- hydroxylase and lysyl hydroxylase.
9
Q
status
A
Plasma Vitamin C.
Sensitive to recent diet. Leukocyte
vitamin C—reflects tissue stores.
10
Q
RDA
A
Males: 90mg, Females 75,
11
Q
Food
A
fruits & Vegetables.
Peppers. Meats and milk aren’t
good sources
12
Q
Absorption
A
Dehydroascorbic acid = GLUT & Ascorbic acid = SVCT-1. Both transfer to SVCT-2. Sodium dependent vitamin C transporter. GLUT= glucose transporter. Exported into portal blood.
13
Q
Functions:
A
reducing agent in synthesis of: collagen, carnitine, neurotransmitter and tyrosine. Nonenzymaticcally as a soluble antioxidant.
14
Q
Carnitine
A
derivative of lysine. Essential metabolite. Role in transporting of activated longchain fatty acids from the cytosol to mitochondrial matrix, where beta oxidation occurs.
15
Q
Deficienct
A
Scurvy. One of the
oldest diseases in history. Rare.
Malnourished.
