Vitamin B12
Vitamin
Overview
- Vitamin B12 (cobalamin) is a water-soluble vitamin containing cobalt, essential for human metabolism.
- It acts as a co-enzyme in two key biochemical pathways:
- Methionine synthesis from homocysteine.
- Conversion of methylmalonyl-CoA to succinyl-CoA.
- These pathways are crucial for DNA synthesis, red blood cell formation, and neurological function.
Chemistry
- Vitamin B12 is a complex organometallic compound called cobalamin.
- Molecular formula: C₆₃H₈₈CoN₁₄O₁₄P.
- Contains a central Co³⁺ ion coordinated within a corrin macrocycle (a contracted porphyrin).
- The IUPAC name is extremely long; "cobalamin" is used commonly.
- Key features:
- Central cobalt atom.
- Corrin ring.
- Nucleotide (5′-deoxyadenosyl, cyanide, methyl, or hydroxyl ligand).
- Dimethylbenzimidazole “lower ligand”.
- Highly polar, water-soluble, stable under acidic conditions, but degrades in light and alkaline pH.
Sources & Quality
- Natural Vitamin B12 is produced exclusively by microorganisms: Propionibacterium, Lactobacillus, and certain Clostridia species.
- Commercially, it's harvested from bacterial fermentation (Pseudomonas denitrificans or Propionibacterium freudenreichii) and purified.
- Synthetic routes (e.g., cyanocobalamin) involve chemical conversion of the natural corrin core, yielding a stable, inexpensive form.
- Methylcobalamin and adenosylcobalamin are produced by microbial biosynthesis and conversion.
- Quality considerations include:
- Cobalamin form (cyanocobalamin vs. methyl-/adenosyl-cobalamin).
- Absence of heavy-metal contaminants.
- Compliance with pharmacopeial standards (USP, EP).
- "Cobalamin-free" (for vegans) is derived from non-animal microbial cultures.
Where to Buy Vitamin B12
Affiliate Disclosure: We earn a commission if you purchase through these links at no additional cost to you. This helps us maintain our research and provides you with the best supplement information.