Vitamins

  1. C
    Functions. Why do we need it? Deficiency.
    • Ascorbic acid
    • Electron donor for 8 mammalian enzymes: collagen synthesis, bile acid formation, NA synthesis, immune function
    • Antioxidant and free radical scavenger with chain breaking properties - promotes iron absorption and prevention of N-nitroso compounds in the stomach
    • L-gulonolactone oxidase: is absent
    • Scurvy
  2. B1: functions, deficiency
    • Thiamin
    • Aldehyde transfer: carbohydrate metabolism, carboxylation, conenzyme in Acetyl CoA formation, nerve function
    • Beriberi: oedema due to cardiac insufficiency. Paralysis due to damaged peripheral nerves.
  3. B2
    • Riboflavin
    • Redox: part of FAD
  4. B3
    • Niacin
    • Redox: part of NAD and NADP
    • Pellagra: sunburn like skin and mouth lesions
  5. B6
    • Pyroidine
    • Amino group transfer: cofactor in aa metabolism and glycogen phosphorylase reacion, synthesis of NA and serotonin, haem
  6. B9
    • Folate
    • One carbon transder: coenzyme in DNA and aa synthesis, erythropoesis
    • Anaemia: important in pregnancy - macrolytic anaemia
  7. B12
    • Cobalamin
    • Alkylation: coenzyme in folate metabolism, Met synthesis
    • Deficient in vegans
  8. A
    • Retinol
    • Vision: 11-cis-retinal in visual transduction
    • Immunity: regulation of proliferation and activation of lymphocytes
    • Embryonic development: Hox gene expression
    • Gene transcription: acts like steroid hormones, binding to retinoic acid receptors (RAR and RXR) as TFs - therapy and chemoprevention eg promyelocytic leukaemia
    • Antioxidants: provitamin A carotenoids eg B-carotene are powerful free radical scavengers
    • Deficiency: common, esp in developing world. Ocular problems (Bitot's spots, xerophalia), depressed immune function. Causes 1.4 million(/2m) child blindness.
  9. D
    • Calciferol (Active is calcitirol)
    • Hormone rather than vitamin
    • Synthesised in skin by UV conversion of 7-dehydrocholesterol.
    • Deficiency: osteoporosis, rickets
    • Calcium homeostasis
    • Insulin production
    • Immune function regulation
    • Blood pressure regulation
    • Activate apoptosis and inhibit angiogenesis in cancer
  10. E
    • 8 naturally occuring forms - a-tocopherol and a-tocotrienol most common in diet (but 4 of each)
    • Chain breaking antioxidant in lipid membranes
    • Sperm production and egg implantation
  11. K
    • Blood coagulation
    • Metabolic pathways esp in bone
    • Produced by bacteria in bowel
Author
mfawcett
ID
156665
Card Set
Vitamins
Description
Vitamins
Updated