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.
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
Related conditions
Related
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).
Educational information, not medical advice. For any symptom, see a health professional.
Sources: BLVRA: Biliverdin reductase A (human) (UniProt, 2026); BLVRB: Flavin reductase (NADPH) (human) (UniProt, 2026); 1HE2: Human biliverdin IX beta reductase: NADP/biliverdin IX alpha ternary complex (RCSB Protein Data Bank, 2026); Reactome | Heme degradation (Reactome, 2026).
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Representative model, for educational purposes only.