Vitamins II

Vitamins II

Vitamin K
1. K1
  1. plants
    1. long, saturdated side chain
2. K2
  1. fish
    1. polyprenyl side chain
3. menadione
  1. synthetic
    1. water soluble
      1. activated in liver
        prenylation
4. enzymatic cofactor
  1. carboxylation
    1. glutamate residues
      1. requires O2
  2. substrates
    1. prothrombiin
      1. needs Ca, post-trans mod
        active thrombin
      2. anticoagulant drugs
        dicumarol, warfarin
        inhibit reductase
        cannot convert oxidized K back to K
    2. osteoalcin
      1. binds Ca
      2. regulates mineralization
5. nutrition
  1. sources
    1. leafy veggies, grains, liver
  2. deficiency
    1. increased coagulation time
    2. impaired clotting, bruising
    3. hemorrhagic disease of newborn
    4. impaired fetal develoment of bony tissue
  3. excess
    1. infant
      1. hemolytic anemia, jaundice
Vitamin A
1. forms
  1. active form
    1. all-trans-retinol
  2. provitamin
    1. B-carotene
      1. antioxidant
        cleave --> retinal
        retinal reductasse --> retiol
        only in intestinal mucosa
        excess
        not as teratogenic
        inhibit lipid peroxidation
2. roles
  1. visual cycle
    1. 11-cis retinal
      1. pigments
      2. rhodopsin
        photosensitive, 7 pass transmembrane
        retinal rods
        11-cis-retinal bound to opsin
        retinal is fat soluble
        to liver in chylomicrons
        stored in stellate cells
        retinyl esters
      3. light converts to all-trans-retinal
        signaling - cGMP phosphodiesterase, transducin
        close Na channel, hyperpolarization
        signals by optic nerve to brain
  2. hormonal reg gene expression
    1. all-trans retinoic acid
      1. activates RAR and RXR
    2. 9-cis retinoic acid
      1. activates only RXR
        heterdimerizes w/
        receptors
        vitt D
        thyroid hormone
        PPAR
        transcription factors
    3. RAR, RXR
      1. bind response elements
        promoter region
      2. active
        homo or heterodimers
    4. > 500 genes
  3. glycoprotein synthesis
3. deficiency
  1. night-blindness
  2. permanent ocular degeneration/blindness
    1. lose vitreal fluid
      1. extrude lens
    2. lack of retinoic acid
  3. lose hormonal activity
    1. respiratory/urinary infection
4. excess
  1. liver disease
  2. teratogenicity
  3. bone defects
Vtamin D
1. cholecalciferol
  1. rxn of UV light w/ 7-dehydrocholesterol
2. active form
  1. hydroxylations --> calcitriol
  2. circulating form
    1. 25-hydroxxycholecalciferol
3. roles
  1. Ca absorption in gut
    1. adequate serum [Ca] an [PO4-]
  2. bone growth/remodeling
  3. modulates
    1. neuromuscular and immune function
      1. reduce inflammation
    2. gene expression
      1. cell proliferation, differentiation, apoptosis
4. sources
  1. sunshine, food, fortified foods
5. deficiency
  1. rickets
  2. osteomalacia
6. excess
  1. hypercalcemia
    1. metastatic calcifications
    2. bone demineralization
    3. renal stones
Vitamin E
1. vitamers
  1. 8 compounds
  2. tocopherols
    1. saturated phytyl tail
  3. tocotrienols
    1. trienols
    2. unsaturated phytyl tail
2. active form
  1. a-tocopherol
    1. phenolic ring most is effective
      1. donates H+
        terminates free radicals
3. sources
  1. veggie oils, fatty tissues of animals
4. antioxidant
  1. free radical scavenger
    1. protects PUFA in membrane
  2. terminates free radical lipid peroxidation
  3. prevent heart disease?
    1. limit oxidation of LDL-cholesterol
    2. Enter text here
5. deficiency
  1. fragility/destruction
    1. erythrocytes
  2. nerve degeneration
    1. hands/feet

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	Erstellt von hardinbc vor mehr als 11 Jahre