Vitamin B5
Summary
Pantothenic acid; precursor of coenzyme A (CoA) and the phosphopantetheine arm of fatty acid synthase. Deficiency is rare but causes dermatitis, enteritis, alopecia, and adrenal insufficiency.
Detail
CoA is essential for acyl-group transfer in fatty acid synthesis and oxidation, the TCA cycle (acetyl-CoA, succinyl-CoA), cholesterol/steroid synthesis, and heme synthesis (succinyl-CoA + glycine via ALA synthase). The 4'-phosphopantetheine prosthetic group of fatty acid synthase and acyl carrier protein is also derived from B5. As a water-soluble vitamin it is not stored to a meaningful degree; toxicity is essentially nonexistent. Found broadly in foods (the name 'pantothenic' means 'from everywhere'), so isolated dietary deficiency is very uncommon.
Sources
- First Aid for USMLE Step 1 2024
- Lippincott Biochemistry
Reviewed by AnkiBoss editorial — medical student review. Information here is for study reference only and is not medical advice. Spotted an error? Let us know.