porphyrinogen

porphyrinogen

 [por″fĭ-rin´o-jen]
the reduced form of a porphyrin. The porphyrinogens are the functional intermediates in the biosynthesis of heme and if oxidized to their corresponding porphyrins, such as occurs in porphyrias, are irreversibly removed from the biosynthetic pathway and accumulate in tissues. Their nomenclature corresponds to that of the porphyrins.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
References in periodicals archive ?
We were interested to find in this study that fecal coproporphyrin was a uniformly better diagnostic marker for VP than protoporphyrin, although the predominant porphyrinogen excreted in bile in individuals with VP is protoporphyrinogen (24).
In EP, a deficient activity of the enzyme uroporphyrinogen III synthase in erythrocyte precursor cells results in overproduction of isomer I porphyrinogens that cannot be used to form heme.