noun
- An organic compound that is a porphyrin precursor, especially protoporphyrin IX, which combines with iron to form heme in hemoglobin and other proteins.
Usage: technical; biochemistry
Examples
- Protoporphyrin IX is an essential intermediate in the biosynthesis of heme.
- The enzyme ferrochelatase catalyzes the insertion of iron into protoporphyrin to form heme.
- Elevated levels of protoporphyrin in the blood can indicate certain metabolic disorders.
- Protoporphyrin accumulates in the body when heme synthesis is disrupted.
- The structure of protoporphyrin consists of four pyrrole rings linked by methine bridges.