Vitamins I

Vitamins I

Characteristics
1. essential
  1. cannot be synthesized
2. organic
3. specialized functions
  1. catalytic roles
  2. hormones
  3. antioxidants
4. from cellular foods
5. classification
  1. water soluble
    1. cellular metabolism
      1. energy supplying
    2. contain H+
      1. attached to electronegative atom
      2. form H bonds w/ H2O
    3. do not accumulate
      1. need regular supply
    4. B1, B2, B6, B12
    5. folate, pantothenate, biotin
  2. fat soluble
    1. specialized functions
vitamin B3
1. Pellagra
  1. dermatitis, diarrhea, dementia, death
    1. 1920 epidemic
  2. Casal's necklace
  3. disease of malnutrition
2. niacin
  1. pellagra preventative factor
  2. sources
    1. food
      1. liver, meats peanuts, legumes, whole wheat
      2. enriched grains
    2. tryptophan
  3. roles
    1. vitamin
      1. part of NADH and NADPH
        15 mg/day
    2. non-vitamin
      1. vasodilator
      2. lower plasma cholesterol levels
        increase HDL
      3. increase serum glucose and uric acid
Vitamin B1
1. thiamine
2. cofactor
  1. pyruvate decarboxylase
  2. a-ketoglutarate decarboxylase
  3. transketolase
  4. aa catabolism
    1. a-ketoacid decarboxylase
3. transmits nerve impulses
4. food sources
  1. brown rice, whole wheat, enrich grains, animal tissues, seeds, sprouts
5. deficiencies
  1. Beriberi
    1. peripheral neuropathy
    2. muscle atrophy, weakness
      1. heart failure
        high cardiac output
    3. wet Beriberi
      1. edema
  2. Wernicke-Korsakoff syndrome
    1. inhibition of absorption
      1. alcohol
    2. mental confusion
    3. vision impairment
    4. stupor
    5. coma
    6. hypothermia
    7. hypotension
    8. ataxia
  3. in elderly
    1. loss of appetite
    2. fatigue
    3. depression
Vitamin B2
1. heat stable
2. precursor
  1. FMN, FAD
    1. cofactors of
      1. ETC
      2. xanthine oxidase
        hypoxanthine --> xanthine --> uric acid
      3. succinate dehydrogenase
      4. glutathione reductase
3. food sources
  1. milk, eggs, liver, wheat germ, green veggies
4. deficiency
  1. oral-buccal lesions
  2. dermatitis
  3. chronic alcoholics
Vitamin B6
1. three molecules
  1. pyridoxine
  2. pyridoxamine
  3. pyridoxal
2. catalyze rxns
  1. transamination
  2. deamination
  3. decarboxylation
3. requirements
  1. high protein diets
  2. pregnancy
4. heat labile
  1. convulsions
5. deficiency
  1. weakness
  2. irritability
  3. insomnia
  4. dermatitis
  5. microcytic anemia
    1. iron deficienccy
      1. impaired heme synthesis
Pantothenic acid
1. sulfhydryl group
  1. CoA
  2. ACP
2. roles
  1. TCA cycle
  2. FA synthesis
  3. metabolism BCAA
  4. conjugated bile acid synthesis
3. deficiency
  1. rare
Biotin
1. roles
  1. carboxylation
    1. pyruvate --> OAA
    2. acetyl-CoA --> malonyl-CoA
    3. proprionyl-CoA --> methylmalonyl-CoA --> succinyl-CoA
    4. leucine catabolism
      1. methylcrotonyl-CoA carboxylase
  2. non-carboxylaiton
    1. alter chromatin structure
      1. biotinylated histones
    2. cell signaling/gene expresision
2. sources
  1. liver, milk, plants
3. deficiency
  1. rare
  2. egg whites
    1. avidin
      1. binds tightly, prevent absorption
  3. dermatitis, alopecia, enteritis
Folic acid
1. enzymatic role
  1. transfer 1 C group
  2. synthesis
    1. choline, serine, glyciine, purines, dTMP
  3. regeneration
    1. homocysteine --> methionine
2. sources
  1. leafy veggies, yeast, liver
3. deficiency
  1. affects rapid dividing cells
  2. megaloblastic anemia
  3. leukopenia
  4. gastric disturbances
  5. early pregnancy
    1. neural tube defects
      1. supplement prior to conception
Vitamin B12
1. cobalamin
2. catalyze rxns
  1. homocysteine --> methionine
  2. methylmalonyl-CoA --> succinyl-CoA
3. sources
  1. animal tissues/bacteria only
  2. body has stores
    1. 3-5 years --> deficiency
4. deficiency
  1. pernicious anemia
    1. problem of malabsorption
      1. lack intrinsic factor
        inadequate absorption
      2. lack of stomach acid
        doesnt release B12 from food
      3. increased in elderly
  2. dietary
    1. vegans
      1. breast fed infants
  3. symptoms
    1. megaloblastic anemia
      1. impaired DNA synthesis
    2. progressive demyelination
Vitamin C
1. L-ascorbic acid
  1. glucose derivative
    1. gluconolactone oxidase
      1. lacking in humans
2. water soluble
3. cofactor
  1. hydroxylation of proline
    1. procollagen
      1. Scurvy
  2. dopamine --> NE
  3. synthesis
    1. bile acids
    2. corticosteroids
    3. carnitine
4. non-enzymatic roles
  1. enhance iron absorption
  2. protects vit A, E, some B
  3. electron acceptor
    1. OH-, O2
5. glutathione regenerates
  1. dehydroascorbate + 2CSH --> ascorbin acid + GSSG

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