uroporphyrinogen

(redirected from uroporphyrinogen III cosynthetase)

uroporphyrinogen

 [u″ro-por″fĭ-rin´o-jen]
a porphyrinogen formed from porphobilinogen; it is a precursor of uroporphyrin and coproporphyrinogen.

por·phy·rin·o·gens

(pōr'fi-rin'ō-jenz),
Intermediates in the biosynthesis of heme, as follows: four porphobilinogens condense to form uroporphyrinogens I and III (giving rise to side products uroporphyrins I and III) that are decarboxylated to form coproporphyrinogens I and III (giving rise to side products coproporphyrins I and III); coproporphyrinogen III is oxidized to protoporphyrinogen III (IX), which is then oxidized to form protoporphyrin III (IX) (this last intermediate adds ferrous iron to yield heme); certain porphyrinogens are elevated in certain porphyrias.

por·phy·rin·o·gens

(pōr'fir-in'ō-jenz)
Intermediates in the biosynthesis of heme; certain porphyrinogens are elevated in certain porphyrias.