VITAMIN
ACTIVE FORM USED AS A CO-FACTOR DEFICIENCY / TOXICITY NOTES
VITAMIN B1 / Thiamine pyrophosphate Pyruvate dehydrogenase DEFICIENCY
THIAMINE -ketoglutarate dehydrogenase Beri-beri
Branched chain AA dehydrogenase Wernicke-Korsakoff Syndrome
Transketolase (Phase 2) reactions in the HMP
shunt
VITAMIN B2 / Flavin Mononucleotide (FMN) Redox reactions, as electron carrier NO DEFICIENCY STATES
RIBOFLAVIN Flavin Adenine Dinucleotide (FAD) Stomatitis, cheilosis, dermatitis, corneal vascularization
VITAMIN B3 / Nicotinamide adenine dinucleotide + Redox reactions, as electron carrier DEFICIENCY May be derived from TRYPTOPHAN
NIACIN Phosphate (NAD and NADP) Pellagra (Diarrhea, Dermatitis, Dementia) using Vitamin B6
Hartnup Disease: tryptophan absorption
Carcinoid Syndrome: serotonin tryptophan metabolism
Isoniazid Use: Vitamin B6
VITAMIN B5 / Constituent of Coenzyme A (needed to Co-factor for acyl transfers NO DEFICIENCY STATES
PANTOTHENATE activate fatty acids) Component of fatty acid synthase Dermatitis, enteritis, alopecia, Adrenal insufficiency
VITAMIN B6 / Pyridoxal Phosphate Used as a coenzyme in AA transamination DEFICIENCY
PYRIDOXINE Used as a coenzyme for: Isoniazid toxicity: INH + Pyridoxal Phosphate Inactive derivative;
Glycogen phosphorylase can lead to peripheral neuropathy
Cystathione synthase TOXICITY
ALA synthase Intake of >2g/day
Synthesis of niacin from tryptophan Gait problems and CNS Toxicity
VITAMIN B12 / 5-deoxyadenosylcobalamin Co-factor for methionine synthase DEFICIENCY Structure: Cobalt in center of corrin
COBALAMIN used for methionine synthesis Homocysteine + N-methyl THF Pernicious Anemia ring
methionine + THF Autoimmune destruction of parietal cells IF secretion - Methylcobalamin: contains methyl
Methylcobalamin Co-factor of methylmalonyl-CoA mutase Vitamin B12 absorption group
Used for isomerization reactions Methylmalonyl CoA Succinyl CoA Early SSx: Megaloblastic Anemia - Cyanocobalamin: contains CN
Late SSx: Neuropsychiatric (subacute combined degeneration) Needs intrinsic factor for absorption;
Diagnosis: Schilling Test, VitB12, anti-IF produced by parietal cells
Other causes: Malabsorption, Absence of terminal ileum Absorbed in the terminal ileum
VITAMIN B9 / Tetrahydrofolate Used as coenzyme for 1-carbon transfer DEFICIENCY Structure: Pterin ring + Para-
FOLIC ACID Dihydropteroate synthetase: PABA Methylation reactions, like synthesis of Megaloblastic anemia with no neurologic symptoms aminobenzoic acid (PABA) +
DHF; inhibited by Sulfamethoxazole purines and thymine Hypersegmentation of neutrophils (earliest manifestation) glutamate residues
Dihydrofolate reductase: DHF Macrocytic anemia Humans cannot synthesize PABA and
THF; inhibited by Trimethoprim Neural tube defects add glutamate humans cannot
Pregnant mothers must be given 400 mcg folate daily synthesize folate
VITAMIN B7 / Used as a co-factor for carboxylation reactions DEFICIENCY Pyruvate carboxylase:
BIOTIN Pyruvate carboxylase (Pyruvate OAA) Induced by AVIDIN in egg whites Gluconeogenesis
Acetyl CoA carboxylase (Acetyl CoA Dermatitis Acetyl CoA carboxylase: Fatty Acid
Malonyl CoA) Enteritis Synthesis
Propionyl CoA carboxylase (Propionyl CoA Propionyl CoA carboxylase: Odd-
Methylmalonyl CoA) numbered fatty acid
VITAMIN C / Used as a co-factor in DEFICIENCY Vitamin C reduces Fe3+ to Fe2+ in
ASCORBIC ACID Hydroxylation of proline and lysine Scurvy stomach to increase Fe absorption
(collagen synthesis) Loose teeth and sore gums, swollen joints, fragile vessels, anemia
Dopamine -hydroxylase (dopamine to
norephinephrine)
