vitamins: inactive coenzymes - west valley college
TRANSCRIPT
Micronutrients
Biol 45 1
Water-soluble Vitamins:
Coenzymes +
Inactive enzyme
Vitamin coenzyme
Active enzyme
Thiamin (B1)
• thiamin pyrophosphate (TPP)– Energy
metabolism
Thiamin deficiency, toxicity
ExcessNone reported
Adequate intake
Thia
min
DeficiencyBeriberiWernicke-Korsakoff syndrome
Micronutrients
Biol 45 2
Riboflavin (B2)
• electron carriers– FAD– FMN
Riboflavin deficiency, toxicity
ExcessNone recognized
Adequate intake
Rib
ofla
vin
DeficiencyUncommonAraboflavinosis
glossitis
Niacin (B3)
• Names– Nicotinic acid = niacin– Nicotinamide = niacinamide
• Coenzymes– NAD+
– NADP+
• Functions– energy metabolism– fatty acid synthesis
Micronutrients
Biol 45 3
Food sources of niacin
Niacin deficiency, toxicity
Adequate intake
Nia
cin
DeficiencyPellagra
ExcessSkin flushing
Vitamin B6: Pyridoxine
• Coenzyme: pyridoxal phosphate (PLP)• Other forms
– Pyridoxal– Pyridoxamine
• Functions– Protein, carb metabolism– RBCs– Neurotransmitter synthesis– Homocysteine metabolism
Micronutrients
Biol 45 4
Food sources of B6
Vitamin B6 deficiency, toxicity
Adequate intake
Vita
min
B6
ExcessNerve damage
DeficiencyAnemiaDermatitisDecreased immunity
Vitamin B9: Folic Acid
• Coenzymes– Tetrahydrofolate– Dihydrofolate
• Functions– DNA synthesis– Homocysteine metabolism
Micronutrients
Biol 45 5
Folic Acid deficiency, toxicity
Adequate intake
Fola
te
ExcessNone reportedMasks Vit. B12 deficiency
DeficiencyMegaloblastic anemiaNeural tube defects
Cells divide normally
Deficiency
Adequate
Cells can’t divide normally
Stem cell
Normal RBCs
Megaloblasticblood cells
Neural Tube Defects
Healthy spine
Spina bifida
Skin on back
Spinal cordSpinal fluidVertebra
Skin on back
Spinal cord
Spinal fluid
Vertebra
After Wardlaw Fig. 10-6
Vitamin B12: Cyanocobalamin
• “cobalamin”• Folate activation• Myelin sheath
maintenance• Homocysteine
metabolism
Micronutrients
Biol 45 6
B12 deficiency, toxicity
Adequate intakeB
12ExcessNone recognized
DeficiencyPernicious anemia (Megaloblastic anemia)Nerve degeneration
Vitamin B5 : Pantothenic acid
• Coenzyme A (CoA)– energy extraction– fatty acid synthesis
pantothen means "from everywhere"
Pantothenic acid deficiency, toxicity
ExcessNone reported
Adequate intake
Pant
othe
nic
acid
Deficiency (RARE!)WeaknessFatigueImpaired muscle function
Micronutrients
Biol 45 7
Vitamin B7: Biotin
• Functions– amino acid metabolism– fatty acid metabolism– DNA synthesis
Biotin deficiency, toxicity
ExcessUnknown
Adequate intakeB
iotin
Deficiency (rare)DematitisHair loss
Vitamin C: Ascorbic Acid
• Functions– antioxidant – collagen synthesis– synthesis of dopamine, noradrenaline
and adrenaline
Micronutrients
Biol 45 8
Vitamin C deficiency, toxicity
Adequate intake
Vita
min
C
ExcessDiarrheaGI symptoms
DeficiencyScurvy
Choline
• Functions– Precursor: acetylcholine – Precursor: phospholipids– Precursor: betaine
Choline deficiency, toxicity
Excess“Fishy” body odorHypotensionSweating, salivation, vomiting
Adequate intake
Cho
line
DeficiencyNo natural deficiencyLiver damage?