High‐performance liquid chromatography/electrospray ionization tandem mass spectrometry of hydroxylated uroporphyrin and urochlorin derivatives formed by photochemical oxidation of uroporphyrinogen I

Abstract

Hydroxylated uroporphyrin I and urochlorin I derivatives formed by photochemical oxidation of uroporphyrinogen I were separated by high-performance liquid chromatography and fully characterized by electrospray ionization tandem mass spectrometry. The porphyrins and chlorins were identified by analysis of their product ion spectra with each hydroxylated derivative giving a characteristic collision-induced dissociation fragmentation pattern. The porphyrins and chlorins characterized were meso-hydroxyuroporphyrin I, alpha-hydroxypropionic acid uroporphyrin I, beta-hydroxypropionic acid uroporphyrin I, hydroxyacetic acid uroporphyrin I, trans-7-hydroxy-8-spirolactoneurochlorin I, cis-7-hydroxy-8-spirolactoneurochlorin I and trans- and cis-7,8-dihydroxyurochlorins I.

Mass spectrometric characterisation of a condensation product between porphobilinogen and indolyl‐3‐acryloylglycine in urine of patients with acute intermittent porphyria

“…Remarkably, after a neutral loss of 75 Da, neutral losses of formic acid, acetic acid and a combination of both were observed at m / z 333.1236, 319.1085 and 273.1023, respectively. These losses are related with the propanoic and ethanoic acid moieties present at C3′ and C4′ of the pyrrolic ring of the PBG and are similar to the MS/MS behaviour previously described for PBG‐related compounds . In negative ionisation mode, several fragments, which can be explained after losses of CO 2 (469 ➔ 425, 408 ➔ 364 and 307 ➔ 263), were observed indicating the presence of several carboxylic acids.…”

Porphomethene inhibitor of uroporphyrinogen decarboxylase: analysis by high‐performance liquid chromatography/electrospray ionization tandem mass spectrometry

“…The photochemical oxidation conditions used for uroporphyrinogen by Phillips et al (2007) were similar to those employed by us (Danton and Lim, 2007). We were unable to detect the presence of uroporphomethene by HPLC/ESIMS despite repeated experiments, while Phillips et al did not report the formation of any oxygenated uroporphyrin derivatives.…”

“…The experiment was carried out as previously described (Danton and Lim, 2007). Uroporphyrin I was reduced to uroporphyrinogen with Na/Hg amalgam and then exposed to UV light for 5 or 10 min.…”

“…We are interested in the photochemical oxidation of uroporphyrinogen and have identified and characterized a series of oxygenated uroporphyrin and urochlorin derivatives by HPLC/ESIMS/MS (Danton and Lim, 2007). Oxygenated porphyrins have also been described by Lin and Timkovich (1994) following photo-oxidation of porphyrinogens.…”

“…In porphyria cutanea tarda (PCT), the most common human porphyria, Uro-D activity is depressed, resulting in an accumulation of uroporphyrinogens (Elder, 2003). Uroporphyrinogen is unstable to air, especially in the presence of light, and is easily oxidized to uroporphyrin, accompanied by oxygenated uroporphyrin derivatives (Lin and Timkovich, 1994;Danton and Lim, 2007).…”