Vitamins: Inactive Coenzymes - West Valley College

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?