Biochem/physiol Actions

Biliverdin reductase catalyzes the transformation of the blue-green pigment biliverdin IX to the yellow-orange bile pigment bilirubin IX by converting a double-bond between the second and third pyrrole ring into a single-bond. This enzyme has two distinct cofactor-dependent pH optima. In the acidic range of pH 6.0-6.7, NADH is utilized, whereas in the alkaline range of pH 8.5-8.7, NADPH is utilized. Biliverdin reductase is considered a major physiologic cytoprotectant. Biliverdin reductase suppresses experimental autoimmune encephalomyelitis in rats. Depletion of biliverdin reductase leads to accumulation of cellular oxidants and augmented cell death.

Physical form

Solution containing 20 mM potassium phosphate buffer, 10% glycerol, 0.2% Igepal CA630, 1 mM EDTA, and 0.1 mM DTT.

Unit Definition

1 unit of biliverdin reductase will trans­form 1 nanomole of biliverdin to bilirubin per minute in an NADPH dependent reaction at pH 8.5 using 100 mM K-phosphate buffer at 37 °C.