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

# Biliverdin reductase

Biliverdin reductase turns green biliverdin into yellow bilirubin using NADPH.

Updated 2026-11-01

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## Key facts

- Biliverdin + NAD(P)H + H⁺ → bilirubin + NAD(P)⁺, in the cytosol.
- BVR-A reduces biliverdin IXα (the adult form); BVR-B mainly reduces the IXβ isomers that predominate in the fetus.
- Structure 1HE2 is human BVR-B with NADP and biliverdin IXα in the active site (the best human structure with substrate).
- It reduces the double bond of the central (γ) bridge, which bends the molecule and makes it fat-soluble.

**Also called**
BVR-A (adult), BVR-B (fetus)

**EC number**
[1.3.1.24](https://www.enzyme-database.org/query.php?ec=1.3.1.24)

**Genes**
BLVRA, BLVRB

**Structure (PDB)**
[1HE2](https://www.rcsb.org/structure/1HE2)

## Regulation

- It is not a control point: the rate is set by heme oxygenase, which comes before it.

## Inhibitors and toxins

- No inhibitors in clinical use

## Clinical notes

- Without BVR-A (very rare variants) biliverdin builds up: green jaundice, otherwise without serious harm.
- Birds, reptiles and amphibians excrete biliverdin; mammals spend NADPH to make bilirubin, an antioxidant that crosses the placenta.
- The green colour of a bruise after a few days is biliverdin not yet reduced.

## Pathways

- [Heme breakdown and bilirubin](https://durgical.com/en/biochemistry/pathways/heme-breakdown-and-bilirubin/)

## Related conditions

- [Neonatal jaundice](https://durgical.com/en/conditions/neonatal-jaundice/)

## Related

- [Heme oxygenase](https://durgical.com/en/biochemistry/enzymes/heme-oxygenase/)
- [Bilirubin](https://durgical.com/en/biochemistry/molecules/bilirubin/)
- [UGT1A1 (bilirubin UDP-glucuronosyltransferase)](https://durgical.com/en/biochemistry/enzymes/ugt1a1/)
- [Heme](https://durgical.com/en/biochemistry/molecules/heme/)

## Test yourself

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

## Which reaction does biliverdin reductase catalyse?

It reduces biliverdin (green) to bilirubin (yellow) using NADPH.

## Which biliverdin reductase isoform predominates in the fetus?

BVR-B, which reduces the IXβ isomers of biliverdin.

## Why does a bruise turn green and then yellow?

Heme becomes biliverdin (green), and biliverdin reductase converts it into bilirubin (yellow).

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

Sources: [BLVRA: Biliverdin reductase A (human)](https://www.uniprot.org/uniprotkb/P53004/entry) (UniProt, 2026); [BLVRB: Flavin reductase (NADPH) (human)](https://www.uniprot.org/uniprotkb/P30043/entry) (UniProt, 2026); [1HE2: Human biliverdin IX beta reductase: NADP/biliverdin IX alpha ternary complex](https://www.rcsb.org/structure/1HE2) (RCSB Protein Data Bank, 2026); [Reactome | Heme degradation](https://reactome.org/PathwayBrowser/#/R-HSA-189483) (Reactome, 2026).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/biochemistry/enzymes/biliverdin-reductase/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/biochemistry/enzymes/biliverdin-reductase/