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C15
West - lecture notes (vitamins)
22
Other
Not Applicable
10/21/2007

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Term
Name every vitamin.
Definition
A D E K; C B1 2 3 4 6 9 12 Biotin
Term
Vitamin A
Definition
B-Carotene à Retinol (trans) à Retinal (11-cis is chromophore active in vision) à Retinoic Acid (accutane active in gene transcription). Deficiency = Night blindness, skin dryness, thickening of conjunctivae, destruction of eye (keratomalacia)
Term
Vitamin D
Definition
Cholesterol + Sunlight = D3, Plant Sterol + Sunlight = D2. D2/3 à Kidney (1-OH) à Liver (2-OH's = ACTIVE). Promotes Ca2+ absorption from food and stimulates release from bone. Deficiency = rickets, osteomalacia.
Term
Vitamin E
Definition
Tocopherols and Tocotrienols found in all cell membranes. Antioxidant role as free radical scavenger. Prevents oxidation of LDL (reduce risk of cardiovascular disease?) No major deficiencies. Mega-doses not good since some ROS's are good and Vitamin E can interfere with Vitamin K metabolism (clotting problems).
Term
Vitamin K
Definition
K1 (phylloquinone) from plants and K2 (menaquinone) from bacteria in gut. Kofactor in the Karboxylation of Glutamyl residues to form Kalcium-binding proteins involved in Koagulation. Carried in chylomicrons and LDL. Deficiency = increased PTT.
Term
Why B-Complex?
Definition
Same food sources (grains, meats, and foliage (9)). Interdependent pathways.
Term
Vitamin C
Definition
Ascorbic Acid. Antioxidant, reducing agent, cofactor in hydroxylation reactions and cross-linking of collogen. Deficiency = scurvy.
Term
Vitamin B1
Definition
Thiamine. Forms coenzyme TPP (oxidative decarboxylation in TCA cycle and amino acid metabolism). Deficiency = Wernicke-Korsakoff Syndrome (mental confusion and ataxia). Severe deficiency known as beriberi. Alcoholics at increased risk since they are malnourished and water soluble vitamins don't stay around long.
Term
Vitamin B2
Definition
Riboflavin. Forms FAD, FMN.
Term
Vitamin B3
Definition
Niacin (Nicotinic Acid). Trp + B6 à Niacin à NAD+ and NADP+. Effects on chol: decreased LDL, increased HDL; flushing. Deficiency = Pellagra (Diarrhea, Dermatitis, and Death).
Term
Biotin
Definition
Imidazole moety binds to avidin (in uncooked egg whites). This makes biotin unabsorbable. Biotin is a cofactor for carboxylases used in FA synthesis/metabolism, gluconeogenesis, and BCAA metabolism.
Term
Vitamin B5
Definition
Pantathoic Acid. Links to phosphate to form CoA. PA divisibile by 15 & 3.
Term
Vitamin B6
Definition
Pyridoxine. Forms PLP (Pyridoxal Phosphate) which is involved in AA metabolism (mostly degradation).
Term
Vitamin B9
Definition
Folic Acid. Coenzyme for one-carbon transfer (H-CO- groups during DNA biosynthesis; CH3 groups for methylation cycle). B9 makes DHF which is coverted to THF and used for: Serine, Glycine, dTMP, purine rings. Deficiency common during pregnancy. Pernicious (megaloblastic) anemia, neural tube defects. Also hyperhomocysteinemia (see B12).
Term
Vitamin B12
Definition
Cobalamin. B12 regenerates THF from the N5-Methyl form. It does this by simultaneously converting homocysteine to methionine (which can be converted to SAM later). Deficiency = Homocysteinuria. Severe = Megaloblastic anemia (large RBC's due to high breakdown. Intrinsic factor is needed to bind B12 in intestine and this is usually cause.
Term
What does the liver store?
Definition
A, E, D (in fat), some K
Term
What does the blood store?
Definition
E
Term
What does the kidney store?
Definition
E
Term
What does the heart store?
Definition
E, K
Term
What does the brain store?
Definition
K
Term
What does the pancreas store?
Definition
K
Term
What vitamins can be toxic if dosage is too high?
Definition
Little toxicity of water-soluble vitamins (some niacin side effects. A, D are the big ones. E can interfere with K metabolism.
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