What enzyme breaks down biliverdin to bilirubin?

Biliverdin reductase is the enzyme responsible for converting biliverdin, a green pigment formed from the breakdown of heme, into bilirubin, which is a yellow pigment. This process is part of the body's mechanism for handling heme, particularly from hemoglobin in red blood cells.

Bilirubin plays a crucial role in bilirubin metabolism. Once formed, bilirubin is eventually conjugated in the liver, making it water-soluble for excretion. The process initiated by biliverdin reductase is vital in neonatal care, as newborns often have elevated bilirubin levels (physiological jaundice), and understanding these enzymatic pathways is essential for managing their care effectively.

The other enzymes mentioned serve different functions: heme oxygenase helps in the initial breakdown of heme into biliverdin, conjugase is involved in the conjugation of bilirubin, and glucuronidase is responsible for the hydrolysis of bilirubin glucuronides, but they do not convert biliverdin to bilirubin.