Nutrition Atlas⌘ K

nutrient

Lysine

A basic essential amino acid with a positively charged side chain.

Lysine is supplied by dietary protein. Its side chain commonly carries a positive charge, and its carbon portion follows a ketogenic breakdown route.

Charge and carbon fate

Lysine’s terminal amino group contributes positive charge in proteins. During catabolism, its carbon portion follows a route that does not provide a net source of glucose.

Related topics

  • Protein
    Lysine is used to build Protein

    Lysine is one of the amino acids used to assemble proteins.

Worth knowing

  • It is dietarily essential. Lysine is one of nine amino acids humans must obtain from food.

A closer look

It is one part of protein quality

Protein adequacy depends on the overall pattern of indispensable amino acids, so lysine is one component of a complete protein supply.

References

Source-checked local draft.
Human editorial review pending.

  1. NIH National Library of MedicineBiochemistry, Essential Amino AcidsChecked 2026-09-05
  2. NIH National Library of MedicineBiochemistry, Protein CatabolismChecked 2026-09-05
  3. NIH National Library of MedicineBiochemistry, Primary Protein StructureChecked 2026-09-05
  4. European Food Safety AuthorityScientific Opinion on Dietary Reference Values for proteinChecked 2026-09-05