Bilirubin Assay Kit (Total and Direct, Colorimetric)

Supplementary info

This supplementary information is collated from multiple sources and compiled automatically.

Activity summary

Bilirubin is a yellow compound a byproduct of heme catabolism formed during the breakdown of hemoglobin in red blood cells. In humans bilirubin appears in the bloodstream and is eventually processed by the liver. It has a molecular weight of approximately 584.7 Da. Bilirubin is often measured in clinical settings as "bilirubin total" or separated into "direct bilirubin" (conjugated form) and total bilirubin values for diagnostic purposes. This target mainly expresses in the liver and to some extent in the spleen and bone marrow.

Biological function summary

Bilirubin acts as an antioxidant and plays a significant role in cellular defense mechanisms against oxidative stress. In the liver it is conjugated by glucuronosyltransferase into direct bilirubin making it more water-soluble for excretion in bile. It does not directly participate as part of a larger protein complex but has interactions within the cell associated with detoxification and antioxidant networks. The fractionation into bilirubin 1.5 as a form ensures efficient disposal of this molecule.

Pathways

Bilirubin is an integral part of the heme degradation pathway which includes the proteins heme oxygenase and biliverdin reductase. These proteins transform heme into biliverdin and subsequently into bilirubin. The liver exits bilirubin through the bile production and excretion pathway involving proteins like multidrug resistance-associated protein 2 (MRP2) for transport into bile ducts. These pathways highlight bilirubin’s quintessential role in heme turnover and in maintaining lipid membrane health through its antioxidant properties.

Associated diseases and disorders

Bilirubin levels associate with jaundice and Gilbert's syndrome. Elevated bilirubin or hyperbilirubinemia may indicate liver dysfunction. In liver diseases such as hepatitis bilirubin processing is impaired showcasing its diagnostic utility. Bilirubin total and direct bilirubin readings help assess liver function and gauge bile duct obstruction. Certain proteins like albumin bind to bilirubin in the bloodstream for its transport important for understanding conditions like neonatal jaundice where immature liver function leads to increased unconjugated bilirubin levels.