Biochemistry · Molecule
Ribose 5-phosphate !
Ribose 5-phosphate is the five-carbon sugar the cell uses to build DNA, RNA, ATP, NAD and coenzyme A.
Updated 2026-11-01
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Key facts
- It is made in the pentose pathway: by the oxidative phase (from ribulose 5-phosphate) or by the non-oxidative phase run backwards (from fructose 6-phosphate and glyceraldehyde 3-phosphate).
- PRPP synthetase activates it to PRPP (5-phosphoribosyl 1-pyrophosphate), the starting point for nucleotides.
- Rapidly dividing cells (bone marrow, tumours) need a lot of it.
- Formula
- C₅H₁₁O₈P
- PubChem
- CID 77982
Structure
- An aldopentose with a phosphate on carbon 5; in nucleotides it is a β-furanose ring.
Clinical notes
- Excess PRPP (overactive PRPP synthetase) makes too many purines: gout and uric acid stones.
- In GSD I trapped glucose 6-phosphate yields more ribose 5-phosphate and more uric acid.
Pathways
Related conditions
Related
Test yourself
Think of the answer, then tap the question to see it.
What is ribose 5-phosphate used for?
To make nucleotides (DNA, RNA, ATP) and coenzymes such as NAD, FAD and coenzyme A.
How does a cell that needs little NADPH obtain ribose?
It runs the non-oxidative phase backwards with transketolase and transaldolase, from glycolytic intermediates.
Which activated molecule is made from ribose 5-phosphate to build nucleotides?
PRPP, by PRPP synthetase.
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: Ribose 5-phosphate (CID 77982) (PubChem, NCBI, 2026) · Public domain; Pentose phosphate pathway (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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