Vitamins I

Vitamins I

1. Characteristics

   • essential
     • cannot be synthesized
   • organic
   • specialized functions
     • catalytic roles
     • hormones
     • antioxidants
   • from cellular foods
   • classification
     • water soluble
       • cellular metabolism
         • energy supplying
       • contain H+
         • attached to electronegative atom
         • form H bonds w/ H2O
       • do not accumulate
         • need regular supply
       • B1, B2, B6, B12
       • folate, pantothenate, biotin
     • fat soluble
       • specialized functions

2. vitamin B3

   • Pellagra
     • dermatitis, diarrhea, dementia, death
       • 1920 epidemic
     • Casal's necklace
     • disease of malnutrition
   • niacin
     • pellagra preventative factor
     • sources
       • food
         • liver, meats peanuts, legumes, whole wheat
         • enriched grains
       • tryptophan
     • roles
       • vitamin
         • part of NADH and NADPH
           • 15 mg/day
       • non-vitamin
         • vasodilator
         • lower plasma cholesterol levels
           • increase HDL
         • increase serum glucose and uric acid

3. Vitamin B1

   • thiamine
   • cofactor
     • pyruvate decarboxylase
     • a-ketoglutarate decarboxylase
     • transketolase
     • aa catabolism
       • a-ketoacid decarboxylase
   • transmits nerve impulses
   • food sources
     • brown rice, whole wheat, enrich grains, animal tissues, seeds, sprouts
   • deficiencies
     • Beriberi
       • peripheral neuropathy
       • muscle atrophy, weakness
         • heart failure
           • high cardiac output
       • wet Beriberi
         • edema
     • Wernicke-Korsakoff syndrome
       • inhibition of absorption
         • alcohol
       • mental confusion
       • vision impairment
       • stupor
       • coma
       • hypothermia
       • hypotension
       • ataxia
     • in elderly
       • loss of appetite
       • fatigue
       • depression

4. Vitamin B2

   • heat stable
   • precursor
     • FMN, FAD
       • cofactors of
         • ETC
         • xanthine oxidase
           • hypoxanthine --> xanthine --> uric acid
         • succinate dehydrogenase
         • glutathione reductase
   • food sources
     • milk, eggs, liver, wheat germ, green veggies
   • deficiency
     • oral-buccal lesions
     • dermatitis
     • chronic alcoholics

5. Vitamin B6

   • three molecules
     • pyridoxine
     • pyridoxamine
     • pyridoxal
   • catalyze rxns
     • transamination
     • deamination
     • decarboxylation
   • requirements
     • high protein diets
     • pregnancy
   • heat labile
     • convulsions
   • deficiency
     • weakness
     • irritability
     • insomnia
     • dermatitis
     • microcytic anemia
       • iron deficienccy
         • impaired heme synthesis

6. Pantothenic acid

   • sulfhydryl group
     • CoA
     • ACP
   • roles
     • TCA cycle
     • FA synthesis
     • metabolism BCAA
     • conjugated bile acid synthesis
   • deficiency
     • rare

7. Biotin

   • roles
     • carboxylation
       • pyruvate --> OAA
       • acetyl-CoA --> malonyl-CoA
       • proprionyl-CoA --> methylmalonyl-CoA --> succinyl-CoA
       • leucine catabolism
         • methylcrotonyl-CoA carboxylase
     • non-carboxylaiton
       • alter chromatin structure
         • biotinylated histones
       • cell signaling/gene expresision
   • sources
     • liver, milk, plants
   • deficiency
     • rare
     • egg whites
       • avidin
         • binds tightly, prevent absorption
     • dermatitis, alopecia, enteritis

8. Folic acid

   • enzymatic role
     • transfer 1 C group
     • synthesis
       • choline, serine, glyciine, purines, dTMP
     • regeneration
       • homocysteine --> methionine
   • sources
     • leafy veggies, yeast, liver
   • deficiency
     • affects rapid dividing cells
     • megaloblastic anemia
     • leukopenia
     • gastric disturbances
     • early pregnancy
       • neural tube defects
         • supplement prior to conception

9. Vitamin B12

   • cobalamin
   • catalyze rxns
     • homocysteine --> methionine
     • methylmalonyl-CoA --> succinyl-CoA
   • sources
     • animal tissues/bacteria only
     • body has stores
       • 3-5 years --> deficiency
   • deficiency
     • pernicious anemia
       • problem of malabsorption
         • lack intrinsic factor
           • inadequate absorption
         • lack of stomach acid
           • doesnt release B12 from food
         • increased in elderly
     • dietary
       • vegans
         • breast fed infants
     • symptoms
       • megaloblastic anemia
         • impaired DNA synthesis
       • progressive demyelination

10. Vitamin C

    • L-ascorbic acid
      • glucose derivative
        • gluconolactone oxidase
          • lacking in humans
    • water soluble
    • cofactor
      • hydroxylation of proline
        • procollagen
          • Scurvy
      • dopamine --> NE
      • synthesis
        • bile acids
        • corticosteroids
        • carnitine
    • non-enzymatic roles
      • enhance iron absorption
      • protects vit A, E, some B
      • electron acceptor
        • OH-, O2
    • glutathione regenerates
      • dehydroascorbate + 2CSH --> ascorbin acid + GSSG