Biochemistry · Molecule
Alanine !
Alanine carries nitrogen from muscle to the liver, where it becomes pyruvate again to make glucose (glucose–alanine cycle).
Updated 2026-11-01
Loading the 3D model…
Key facts
- ALT swaps alanine + α-ketoglutarate for pyruvate + glutamate.
- It is the main glucogenic amino acid released by muscle during fasting.
- Glucose–alanine cycle: muscle exports alanine; the liver uses the pyruvate for gluconeogenesis and the amino group for urea.
- Non-essential; its carbon skeleton is pyruvate.
- Formula
- C₃H₇NO₂
- PubChem
- CID 5950
Structure
- The simplest chiral amino acid: a methyl side chain; it is pyruvate with an amino group in place of the carbonyl.
Clinical notes
- It rises in blood in lactic acidosis and pyruvate dehydrogenase deficiency, because piled-up pyruvate is transaminated.
- The enzyme that transaminates it, ALT, is the most specific marker of liver damage.
Related conditions
Related
- Pyruvate
- Alanine aminotransferase (ALT, GPT)
- Glutamate (glutamic acid)
- Transamination and deamination
- Glucogenic and ketogenic amino acids
Test yourself
Think of the answer, then tap the question to see it.
Which keto acid forms when alanine loses its amino group?
Pyruvate, which the liver can use to make glucose.
What does the glucose–alanine cycle do for muscle?
It lets muscle send the nitrogen of its amino acids to the liver without releasing ammonia, and get glucose back.
Why does alanine rise in pyruvate dehydrogenase deficiency?
Pyruvate cannot enter the Krebs cycle, piles up, and part of it is transaminated to alanine.
Molecules are shown in their neutral form, as the databases deposit them; in the cell the acids and phosphates are ionised.
Educational information, not medical advice. For any symptom, see a health professional.
Sources: L-Alanine (CID 5950) (PubChem, NCBI, 2026) · Public domain; Metabolism of amino acids and derivatives (Reactome, 2026); Textbook of Biochemistry for Medical Students, 6th ed. (Jaypee Brothers Medical Publishers (Vasudevan DM, Sreekumari S, Vaidyanathan K), 2011).
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.