Reactome: A Curated Pathway Database

Heme degradation (R-HSA-189483)

Species Homo sapiens

Summation

Most of the heme degraded in humans comes from hemoglobin. Approximately 6-8 grams of hemoglobin is degraded daily which is equivalent to approximately 300 milligrams of heme per day. Heme is not recycled so it must be degraded and excreted. The iron, however, is conserved. There are two steps to heme degradation;
1. cleavage of the heme ring by a microsomal heme oxygenase producing biliverdin
2. biliverdin is reduced to bilirubin.
Bilirubin can then be conjugated with glucuronic acid and excreted.

Locations in the PathwayBrowser
Additional Information
GO Biological Process heme catabolic process (0042167)
Literature References
pubMedId Title Journal Year
12909459 Heme oxygenase-1: unleashing the protective properties of heme Trends Immunol 2003