Biochemistry · Molecule
Globotriaosylceramide (Gb3) !
Gb3 is a ceramide carrying three sugars. α-Galactosidase A breaks it down; in Fabry disease it builds up in vessels, kidney, heart and nerves.
Updated 2026-11-01
Key facts
- Structure: ceramide–glucose–galactose–α-galactose (Galα1→4Galβ1→4Glc-ceramide); α-galactosidase A removes the terminal α-galactose.
- Fabry disease (GLA gene, X-linked): Gb3 and its deacylated form lyso-Gb3 accumulate in endothelium, podocytes, cardiomyocytes and nerve cells.
- Plasma lyso-Gb3 is a biomarker that supports the diagnosis of Fabry disease and helps follow treatment.
- Gb3 is the cell receptor for Shiga toxin (and the Shiga-like toxins of E. coli O157:H7), which explains the kidney damage of haemolytic uraemic syndrome.
- Also called
- Gb3, Ceramide trihexoside, CD77
- Formula
- C₆₀H₁₁₃NO₁₈ (C24:0 form; it varies with the fatty acid)
Structure
- No 3D model: there is no PubChem 3D conformer or PDB chemical component for whole Gb3, a large and flexible lipid.
- The trisaccharide head faces out of the membrane and the two hydrocarbon tails anchor it; the formula changes with the fatty acid (C16 to C24).
- It is made from lactosylceramide by adding α-galactose (Gb3 synthase, A4GALT) and is extended to globoside (Gb4) by adding N-acetylgalactosamine.
Clinical notes
- Fabry disease: burning pain in hands and feet, angiokeratomas, reduced sweating, corneal whorls, proteinuria progressing to kidney failure, left ventricular hypertrophy and stroke.
- Women with one altered GLA copy can have symptoms, often milder, because of X inactivation.
- Enzyme replacement, and an oral chaperone for amenable GLA variants, lower Gb3 storage.
Related conditions
Related
- α-Galactosidase A
- Ceramide
- Glucosylceramide (glucocerebroside)
- Sphingolipids and sphingolipidoses
- Lysosomal storage diseases
- Hexosaminidase B (β-hexosaminidase B)
- Galactose
Test yourself
Think of the answer, then tap the question to see it.
Which enzyme breaks down globotriaosylceramide?
α-Galactosidase A (GLA gene), which removes the terminal α-galactose; its deficiency causes Fabry disease.
Which Gb3-derived molecule is measured in plasma as a Fabry biomarker?
Lyso-Gb3 (globotriaosylsphingosine), Gb3 without its fatty acid.
Why can Shiga toxin damage the kidney?
It binds Gb3 on the surface of renal and endothelial cells, enters them and stops protein synthesis, leading to haemolytic uraemic syndrome.
Why does this page have no 3D model?
Whole Gb3 has no PubChem 3D conformer and no PDB chemical component; it is too large and flexible for those libraries.
Educational information, not medical advice. For any symptom, see a health professional.
Sources: GLA gene: MedlinePlus Genetics (MedlinePlus, US National Library of Medicine, 2026); Fabry disease: MedlinePlus Genetics (MedlinePlus, US National Library of Medicine, 2026); Glycosphingolipid catabolism (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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Representative model, for educational purposes only.