porphobilin

por·pho·bi·lin

(pōr'fō-bī'lin),
General term denoting intermediates between the monopyrrole, porphobilinogen, and the cyclic tetrapyrrole of heme (a porphin derivative).
See also: bilin.

por·pho·bi·lin

(pōr'fō-bī'lin)
General term denoting intermediates between the monopyrrole, porphobilinogen, and the cyclic tetrapyrrole of heme (a porphin derivative).
References in periodicals archive ?
In AIP and other acute porphyrias, urine that is light in color on voiding may darken when exposed to light and air due to polymerization of colorless PBG to uroporphyrin and porphobilin.
PBG in urine undergoes in vitro conversion to the red pigment, uroporphyrin (present mainly as its zinc chelate), and to porphobilin, an as-yet-uncharacterized brown oxidation product of PBG.
The increased urine porphyrin was predominantly uroporphyrin arising from nonenzymatic condensation of micromolar concentrations of PBG to produce a relatively higher concentration of uroporphyrin along with the brown-red pigment porphobilin (1,11).