The next step is the reduction of biliverdin to a yellow color tetrapyrol pigment called bilirubin by cytosolic enzyme biliverdin reductase. 이 빌리루빈은 비공액 빌리루빈, 유리 빌리루빈 또는 간접 빌리루빈입니다. Approximately mg of bilirubin per kg of blood is produced each day.