Biliverdin reductase (BLVR) is a ubiquitously expressed, small cytoplasmic oxidoreductase that catalyzes the reduction of biliverdin to bilirubin. The first step of this process is catalyzed by heme oxygenase, an enzyme that converts heme to iron, carbon monoxide, and biliverdin. BLVR is unique among all enzymes to date in being dual pH/dual cofactor-dependent, as it requires NADH (pH 6.7) or NADPH (pH 8.7) as an electron donor. There are two isoforms of BLVR, biliverdin-IX alpha-reductase (BLVRA), the major component of human adult liver, and biliverdin–IX beta-reductase (BLVRB), found predominantly in fetal liver. The product of BLVR, bilirubin, is an important biological antioxidant, however it is also a neurotoxin and the cause of kernicterus. In addition to being an antioxidant, it inhibits kinase activity and the activity of enzymes such as protein kinase C and NADPH oxidase.
Biliverdin reductase A; Biliverdin-IX alpha-reductase; BLVRA; BVR A; EC 126.96.36.199; testis tissue sperm-binding protein Li 61n