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[Biochemistry](https://durgical.com/en/biochemistry/) · Protein

# Hemoglobin and 2,3-BPG

Hemoglobin carries oxygen in the blood; 2,3-BPG, made by a side branch of red-cell glycolysis, helps it let go in the tissues.

Updated 2026-10-31

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## Key facts

- An α₂β₂ tetramer (HbA) with one heme (Fe²⁺) per chain: up to four O₂.
- 2,3-BPG binds the central cavity between the β chains of deoxyhemoglobin and stabilises the T state: the curve shifts right.
- Bisphosphoglycerate mutase makes it from 1,3-BPG (the Rapoport–Luebering shunt), at the cost of one ATP.

**Genes**
HBA1, HBA2, HBB

**Structure (PDB)**
[1B86](https://www.rcsb.org/structure/1B86)

## Structure

- Fetal hemoglobin (α₂γ₂) binds 2,3-BPG poorly, which is why it takes oxygen from the mother's blood.

## Regulation

- 2,3-BPG rises with altitude, anemia and chronic hypoxia. Stored blood loses it.

## Clinical notes

- Pyruvate kinase deficiency: high 2,3-BPG, better oxygen delivery. Hexokinase deficiency: low 2,3-BPG, worse anemia tolerance.
- In Bogotá (2,600 m), adapting to altitude includes more 2,3-BPG and more hemoglobin.

## Drugs that act here

- [Oxygen](https://durgical.com/en/pharmacology/oxygen/)
- [Methylthioninium chloride (methylene blue)](https://durgical.com/en/pharmacology/methylthioninium-chloride/)
- [Sodium nitrite](https://durgical.com/en/pharmacology/sodium-nitrite/)

## Pathways

- [Glycolysis](https://durgical.com/en/biochemistry/pathways/glycolysis/)

## Related conditions

- [Pyruvate kinase deficiency](https://durgical.com/en/conditions/pyruvate-kinase-deficiency/)
- [Iron deficiency anaemia](https://durgical.com/en/conditions/iron-deficiency-anaemia/)

## Related

- [Pyruvate kinase](https://durgical.com/en/biochemistry/enzymes/pyruvate-kinase/)
- [Hexokinase](https://durgical.com/en/biochemistry/enzymes/hexokinase/)

## Test yourself

Think of the answer, then tap the question to see it.

## Which way does 2,3-BPG shift the hemoglobin dissociation curve?

To the right: it lowers oxygen affinity and helps release it in the tissues.

## Why does fetal hemoglobin have higher oxygen affinity?

Its γ chains bind 2,3-BPG poorly.

## Which enzyme makes 2,3-BPG in red cells?

Bisphosphoglycerate mutase, from 1,3-bisphosphoglycerate.

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Educational information, not medical advice. For any symptom, see a health professional.

Sources: [HBB: Hemoglobin subunit beta (human)](https://www.uniprot.org/uniprotkb/P68871/entry) (UniProt, 2026); [1B86: Human deoxyhaemoglobin-2,3-diphosphoglycerate complex](https://www.rcsb.org/structure/1B86) (RCSB Protein Data Bank, 2026); [2,3-Bisphosphoglyceric acid (CID 61)](https://pubchem.ncbi.nlm.nih.gov/compound/61) (PubChem, NCBI, 2026) · Public domain; 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.

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/biochemistry/enzymes/hemoglobin-and-2-3-bpg/