Vitamins – Chemistry Flashcard

Hormone precursors:
Vitamin D
Vitamin A
Redox cofactors &/or antioxidants:
Vitamin C
Vitamin E (tocopherols)
Vitamin K (phylloquinone, not
an antioxidant)
Vitamin B3 (Niacin)
Vitamin B2 (Riboflavin)
Group transfer agents:
Vitamin B6
Vitamin B12
Folic acid
Pantothenic acid
formed in skin from 7-dehydrocholesterol plus sunlight
converted in the liver to a hormone that regulates calcium uptake.
Vitamin D
-family of is fat-soluble compounds
-found in fish oils, liver, eggs, whole milk, and butter
Vitamin A
________ (found in orange & yellow vegetables), can be enzymatically converted to Vitamin __
Beta-carotene; A
Deficiency – dryness of the skin, eyes, & mucous membranes, retarded growth, night blindness
Vitamin A
Deficiency is the leading cause of preventable blindness in children
Vitamin A
___________, one form of Vitamin A, functions as a hormone and as a pigment in the eye
________ ________ – active drug in Retin-A used in the treatment of severe acne and other skin problems
Retonoic Acid
___ – ___ – ________ is a cofactor for rhodopsin, playing a role in vision
What is the technical name for too much Vitamin A and D?
hypervitaminosis A/D
prevents free radicals (i.e. superoxide anions) from oxidizing compounds (i.e. polyunsaturated fats), thus maintaining integrity of cellular membranes
Vitamin E, C
found in eggs and vegetable oils
Vitamin E
Deficiency is very rare in humans; primary symptom is fragile erythrocytes, atherosclerosis, cardiovascular disease
Vitamin E
Vitamin K
blood-clotting cofactor
Vitamin K
undergoes redox rxn to form prothrombin
Vitamin K
found in green plant leaves; deficiency is very rare.
Vitamin K
_______ (coumadin), with a similar structure, is used to prevent excessive blood clotting.
Isoprenoids = __ linear carbons, __ carbon off to the side
Vitamins __ and __ are isoprenoid derivatives
__________ (also called coenzyme Q) is an isoprenoid
Comes in three flavors: reduced, oxidized, ionized
Vitamin C
regenerates vitamin E from its radical form
Vitamin C
Most animals make vitamin __, but humans can’t; we obtain it through fruits & vegetables
required for the hydroxylation of proline in collagen (cofactor for prolyl 4-hydroxylase)
Vitamin C
What is Vitamin C in oxidized form?
Dehydroascorbic Acid
What is the reduced form of Vitamin C?
Ascorbic Acid
What is the ionized form of Vitamin C?
Scurvy from _________ deficiency
__-_____________ required in collagen (connective tissue in
4 – hydroxyproline
Deficiency of vitamin __ causes scurvy, characterized by _______ __________ degradation
C; connective tissue degradation
Poor healing, bleeding, tooth loss, bone pain, heart failure
Vitamin C
Milder cases: fatigue, irritability, increased severity of respiratory tract infections
Vitamin C
Cofactor for pyruvate & alpha-ketoglutarate dehydrogenase; hence, important for metabolism
Vitamin B1- thiamine
Also does Aldehyde transfers
B1- thiamine
Deficiency causes Beriberi – characterized by heart failure, peripheral neuropathy, Wernicke-Korsakoff syndrome (alcoholics-ataxia, ophthalmoplegia, confusion)
B1- thiamine
Activates Vitamin B6 (pyridoxine)
B2- Riboflavin
Involved in many oxidation-reduction reactions
B2- Riboflavin, B3- Niacin
Required for metabolism of amino acids, fatty acids, and carbohydrates
B2- Riboflavin
Found in meats, nuts, cheese, milk, leafy vegetables, fish, legumes, grains
B2- Riboflavin
Not toxic in high doses (but turns urine dark yellow)
B2- Riboflavin
Deficiency (not common) causes eye & skin problems, mouth inflammation
B2- Riboflavin
_______ is synthesized from tryptophan
But humans generally cannot synthesize enough.
B3- Niacin
Deficiency affects all of the NAD(P)-dependent dehydrogenases, causing pellagra
B3- Niacin
___________ is characterized by the four D’s =diarrhea, dermatitis, dementia, and death, from what deficiency?
Pellagra; B3-Niacin
100 years ago, when corn was a dietary
staple, pellagra was common because
corn is low in ______________.
What is pellagra commonly seen in today?
alcoholics who have reduced niacin absorption
____-_______ medicine can cause niacin
_____ is synthesized from Niacin: no niacin = no ____
helps maintain healthy nerve and red blood cells
B12- cobalamin
found in fish, meat, poultry, eggs, milk, milk products
B12- cobalamin
Vegetarians & vegans are in danger of deficiency
___ deficiency results in reduced levels of hemoglobin (megaloblastic anemia), as well as nervous system impairment that may be irreversible
______ ______ can correct the anemia from B12 deficiency, but not nerve damage.
Folic Acid
has a weak cobalt-carbon bond
organometallic biological molecule
Corrin ring structure: tetrapyrrole (4 heterocyclic aromatic rings) ring system
B12- Cobalamin
With 5′-deoxy-adenosine bound to cobalt, is called coenzyme B12.
B12- Cobalamin
Needed for more than 100 enzymes that play roles in protein metabolism (aids in group transfers to & from animo acids)
B6- Pyridoxine
enzyme cofactor _______ ________ is derived from vitamin B6
pyridoxyl phosphate (PLP)
Deficiency can result in anemia but is rare
B6- Pyridoxine
Found in a wide variety of foods
B6-Pyridoxine, B7- Biotin
Precursor to Coenzyme A, a carrier of carbon fragments such as acetate (i.e. acetyl-CoA); acyl transfers
B5- Pantothenic Acid
Found in many foods; deficiency not seen
B5- Pantothenic Acid
Deficiency is rare, but can result from a diet rich in raw eggs, because eggs are rich in avidin, which binds biotin very tightly
B7- Biotin
Deficiency also can be caused by longterm antibiotic use (synthesized in GI tract)
Carboxylizes pyruvate (to form oxaloacetate), acetyl CoA, and propionyl CoA; hence, necessary for Krebs Cycle
The _______ ________ derivative, tetrahydrofolate, carries 1-carbon units (more reduced form of CO2)
Folic Acid
Deficiency can stop DNA synthesis, also can cause megaloblastic anemia
B9-Folic Acid
_______ _______ is found in leafy vegetables, beans and peas.
Folic Acid
Grains are now (since 1996) enriched with _______ ______.
Folic Acid
Prevents neural tube defects in the developing fetus, and heart disease
Folic Acid
Retinol; Vitamin A
Carbohydrate Metabolism
Thiamine B1
redox, respiration
Riboflavin B2
niacin B3
TCA, FA, and cholesterol
Pantothenic Acid B5
aa metabolism, glycogenolysis
B6; pyridoxal, pyridoxamine, pyridoxine
gluconeogenesis, fa, tca, aa
Biotin B7
1 C metabolism
B9 Folic Acid
ascorbic Acid
component of oxidases in oxidative metabolism, neurotransmitter synthesis, collagen synthesis (deficiency = muscle weakness, neurological deficit, abnormal collagen)
essential component of thyroid hormone (deficiency =goiter, hypothyroidism)
essential component of hemoglobin, other metallo-enzymes (deficiency = defective hemoglobin, anemia)
component of glutathione peroxidase (deficiency = cardiomyopathy)
component of oxidases (deficiency = retarted growth & impaired wound healing)

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