Biochemistry · Molecule
δ-Aminolevulinic acid (ALA) !
ALA is the first committed molecule of heme synthesis; it rises in acute porphyrias and lead poisoning.
Updated 2026-11-01
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Key facts
- It is made in the mitochondrion from glycine and succinyl-CoA (ALA synthase, with vitamin B6) and moves out to the cytosol.
- High urine ALA with normal porphobilinogen: lead, ALA dehydratase deficiency or tyrosinemia type I.
- High ALA and porphobilinogen together: acute intermittent porphyria, hereditary coproporphyria or variegate porphyria in an attack.
- It resembles GABA and is toxic to neurons: one proposed explanation for the neuropathy of acute porphyrias.
- Also called
- 5-ALA, 5-aminolevulinic acid
- Formula
- C₅H₉NO₃
- PubChem
- CID 137
Structure
- A five-carbon keto acid with an amino group at the end (C5); two molecules condense into the porphobilinogen ring.
Clinical notes
- Given as a drug, tumour cells turn it into fluorescent protoporphyrin IX: photodynamic diagnosis and guided glioma surgery.
- Its liver production rises when something induces ALAS1; givosiran lowers it in acute hepatic porphyria.
- Chronic exposure to liver ALA is associated with chronic kidney disease and hepatocellular carcinoma in acute porphyria.
Pathways
Related conditions
Related
Test yourself
Think of the answer, then tap the question to see it.
Which two molecules is ALA made from?
Glycine and succinyl-CoA, by ALA synthase in the mitochondrion.
Which pattern of urine ALA and porphobilinogen suggests lead poisoning?
High ALA with normal porphobilinogen, because lead blocks ALA dehydratase.
Why is 5-ALA used in brain tumour surgery?
Glioma cells convert it into protoporphyrin IX, which fluoresces red and helps show the tumour margins.
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: 5-Aminolevulinic Acid (CID 137) (PubChem, NCBI, 2026) · Public domain; Porphyrins urine test: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2026); Reactome | Heme biosynthesis (Reactome, 2026); Textbook of Biochemistry for Medical Students, 6th ed. (Jaypee Brothers Medical Publishers (Vasudevan DM, Sreekumari S, Vaidyanathan K), 2011).
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