Flashcards in Biochemistry Deck (293)
List the fat-soluble vitamins
A, D, E, K
-absorption depends on ileum and pancreas
-may have to supplement in CF, sprue, or mineral oil intake (b/c all cause malabsorption/steatorrhea)
B-complex deficiencies often result in:
dermatitis, glossitis, diarrhea
Which vitamin is:
retinol = vitamin A
thiamine = vitamin B1
riboflavin = vitamin B2
niacin = vitamin B3
pantothenate = vitamin B5
pyridoxine = vitamin B6
cobalamin = vitamin B12
ascorbic acid = vitamin C
baby born with cleft palate, cardiac abnormalities. which vitamin may have been in excess in mother?
Vitamin A = retinol
--> in excess has terotegenic effects; so, don't give isoretinoin (acne med) to pregnant women
which vitamin may be used to treat measles and AML-M3?
Vitamin A (Retinol)
Deficiency in Vitamin A causes night blindness and dry skin. Why?
Vitamin A = constituent of visual pigments in retina; essential for normal differentiation of epithelial cells into specialized tissue.
TPP =Thiamine pyrophosphate (Thiamine = B1) = cofactor in what 4 reactions?
1) Pyruvate dehydrogenase (glycolysis)
2) alpha-ketoglutarate dehydrogenase (TCA cycle)
3) Transketolase (HMP shunt)
4) Branched-chain AA dehydrogenase
Deficiency in vitamin B1 (Thiamine)?
*impaired glucose breakdown (b/c need TPP as cofactor in glycolysis and TCA cycles, so get ATP depletion); Beriberi (dry/wet), Wernicke-Korsakoff
d/t thiamine deficiency
Wernicke: Triad: confusion, ophthalmoplegia, ataxia
Korsakoff: confabulation, personality change, memory loss (permanent)
peripheral neuropathy, symmetrical muscle wasting, especially distal muscles; due to a vitamin deficiency
dilated cardiomyopathy (high-output cardiac failure), edema, symmetrical peripheral neuropathy; due to a vitamin deficiency
Cheilosis (inflammation of lips, scaling and fissures at corners of the mouth), Corneal vascularization; what vitamin is deficient?
Vitamin B2 (riboflavin); cofactorin oxidation and reduction (FADH2)
Diarrhea, Dermatitis, Dementia; also: glossitis
Pellagra = vitamin B3 (niacin) deficiency
symptom of vitamin B3 excess?
Facial flushing (niacin = treatment of choice to increase HDL levels; side effect = facial flushing!)
Why may one get a B3 deficiency from:
-Malignant carcinoid syndrome?
Vit B3 is derived from Tryptophan and requires vitamin B6 for synthesis, so:
-Hartnup disease: have decreased tryptophan absorption, so decreased B3
-malignant carcinoid syndrome: have increased tryptophan metabolism
-Isoniazid: decreased B6 (so, give B6 = pyridoxine to pts on INH!)
Which vitamin is an essential component of CoA and fatty acid synthase?
Vitamin B5 = pantothenate ("pento-thenate")
What 2 med types may induce vitamin B6 deficiency?
Isoniazid and oral contraceptives
Main causes of cobalamin (vit B12) deficiency?
1) Malabsorption: sprue, enteritis, Diphyllobothrium latum
2) no intrinsic factor (pernicious anemia, gastric bypass surgery)
3) no terminal ileum (Crohn's)
*deficiency can cause macrocytic, megaloblastic anemia; neurologic symptoms
detect etiology of Vitamin B12 (cobalamin) deficiency
Most common vitamin deficiency in US?
deficiency in folic acid (not in pregnancy/just normal):
macrocytic, megaloblastic anemia (no, neuro symptoms, unlike B12 deficiency)
-what does it do?
-how is it formed? (what cofactors are needed in its formation)
-what important reaction is it required for?
transfers methyl units!
ATP + Methionine => SAM
*need vitamin B12 and folate to regenerate methionine, and thus SAM
*SAM is required for conversion of NE-->Epinephrine
excessive ingestion of raw eggs, may cause what deficiency?
Biotin deficiency! Dute to avidin in eggs, binds biotin
Biotin is a cofactor in what 3 reactions:
1) pyruvate carboxylase: (pyruvate-->oxaloacetate)
2) acetyl-CoA carboxylase: acetyl CoA-->malonyl-CoA
3) propionyl-CoA carboxylase: propionyl-CoA-->methylmalonyl-CoA
swollen gums, bruising, hemarthrosis, anemia, poor wound healing
scuvry (vit C def; symptoms for collagen synthesis defect)
3 functions of vitamin C:
1) hydroxylation of proline and lysine in collagen synthesis
2) helps iron absorption (keeps Fe in a reduced state)
3) conversion of dopamine to NE (dopamine beta-hydroxylase)
What forms of vitamin D are these?
D3 = Cholecalciferol
1,25-(OH)2D3 = calcitriol
D2 - ingested in plants
D3 - consumed in milk, formed in sun-exposed skin
25-OH-D3 - storage form
1,25-OH2D3 = calcitriol = active form
function of vitamin E? Deficiency causes?
function = antioxidant; protects RBCs and membranes from free radical damage
deficiency: hemolytic anemia; weakness, posterior column and spinocerebellar tract demyelination