Porphyrin Fractions Research Articles

Increased Fecal Porphyrins in Acute Intermittent Porphyria

Definitive diagnosis of porphyrias may require determination of total porphyrin in urine, feces, and blood (1) and fractionation of the various urine and fecal porphyrins. Most authorities agree that fecal porphyrin fractionation is required for the differential diagnosis of porphyria cutanea tarda, variegate porphyria (VP), and hereditary coproporphyria (HCP) (1)(2). We investigated three patients who excreted excess porphobilinogen (PBG), and who therefore had one of the acute porphyrias. Additional investigation by HPLC fractionation of urine and fecal porphyrins led to a diagnosis of acute intermittent porphyria (AIP). Although total fecal porphyrin in AIP is usually thought to be within the reference interval or slightly increased and of limited assistance in the diagnosis of this type of acute porphyria (1)(2)(3), our patients had markedly increased total fecal porphyrins. Fractionation by HPLC revealed that uroporphyrin was a prominent component in all three cases. Patient A was a woman, 40 years of age, admitted to the emergency department of a tertiary teaching hospital for investigation of intractable acute abdominal pain. Patient B was a woman, 36 years of age, who was initially under the care of an orthopedic surgeon for severe back pain and was referred to a consultant physician for investigation of multiple symptoms, including urinary retention, dysuria, back pain, and depression. Patient C was a woman, 30 years of age, previously diagnosed with AIP at the age of 25 years who consulted a clinician with severe abdominal pain. She had a family history of AIP, and we had identified 15 cases of symptomatic AIP in three generations of her family previously. We investigated the metabolism of …

Geochemical characterization of Malm Zeta laminated carbonates from the Franconian Alb, SW-Germany (II)

During Jurassic times, especially within the Malm ζ stage, local depressions formed on the Eastern Bavarian Carbonate Platform that were surrounded by wall reefs. This created a unique depositional environment, where in an open-marine setting stagnant and anoxic bottom waters developed in an intra-reef depression. Anoxic conditions were stabilized below wave base by enhanced salinity in the bottom waters and establishment of a density stratification. Biomarker analysis was applied to characterize palaeosalinity and redox conditions, utilizing organic sulfur compound, methylated chroman, hopanoid and saturated isoprenoid distributions. Prevention of terrigenous influx by protecting reef walls lead to iron deficiency in intra-reefal sediments causing early diagenetic sulfurization of functionalized lipids. Absence of clay-mineral catalysts and early sulfurization favored an unusual steroid distribution lacking rearranged analogues but providing coexistence of saturated steranes with βαα-, ααα- and αββ-configuration, Δ 13(17)-spirosterenes, unknown sterenes and steradienes as well as mono-, di- and triaromatic steroids. Desulfurization of the polar fraction was carried out for two samples to verify that palaeoenvironment reconstruction based on free hydrocarbon and heterocompound distribution was not invalidated by sulfur quenching of selected compounds. Gammacerane was found to be the only component to occur exclusively in the sulfur-bound fraction. Only minor amounts of hydrocarbons were released upon desulfurization implying that free bitumen analysis was applicable for organofacies characterization. Organic petrological investigation of organic mats revealed the presence of two different types of such structures. Comparison of organoclast fluorescence spectra with those of extracted porphyrin fractions indicate an origin of porphyrins exclusively from cyanobacterial mats whereas algal dominated mats yield no porphyrins. This aims towards a better localization of specific biomarker origin in geological samples.

Evidence for porphyrins bound, via ester bonds, to the Messel oil shale kerogen by selective chemical degradation experiments

High amounts of nickel mono- and di-acid porphyrins were released from Messel oil shale kerogen (Eocene, Germany) by selective chemical degradation (acid and base hydrolysis). The released porphyrin fractions were quantified (UV-vis) and their constituents isolated and characterized at the molecular level (UV-vis, MS, NMR). The mono-acid porphyrin fraction released contained four compounds of similar abundance which arise from an obvious chlorophyll or bacteriochlorophyll precursor. The di-acid porphyrin fraction was, however, dominated by far by one compound, mesoporphyrin IX, which must have originated from heme-like precursors (heme, cytochromes, etc.). These results show unambigously that the released mono- and di-acid porphyrins were linked to the macromolecular kerogen network via ester bonds and suggest that precursor heme-like pigments could be selectively and/or more readily incorporated into the macromolecular kerogen network than precursor chlorophylls and bacteriochlorophylls.

Porphyrins in Upper Jurassic source rocks and correlations with other source rock descriptors

The porphyrin content and composition in the extractable organic matter has been analysed in 13 Kimmeridge clay source rocks, spread from the north to the south of the Norwegian continental shelf. The samples are predominantly immature/early mature. The distribution of nickel and vanadyl porphyrins within the samples is markedly different. Effects of the thermal maturity on the composition of porphyrins is evaluated and compared with biomarker parameters based on sterane and hopane ratios. Maturity is modelled using partial least-squares (PLS) multivariate analysis with T max as a maturity indicator. Porphyrin parameters based on the total carbon number distribution of DPEP and ETIO series from the mass spectral data of the nickel and vanadyl porphyrin fractions effectively describe the T max of the samples with a better correlation than aliphatic biomarker ratios. Selected porphyrin and biomarker ratios were used for principal component analysis (PCA) modelling, and found to describe two types of variation that may be indicative of the prevailing depositional redox conditions.

Effects of chloroquine in hematoporphyrin-treated animals

Porphyrins and related compounds are useful in photodynamic therapy but can cause cutaneous photosensitivity. We determined whether chloroquine, which is effective in treating porphyria cutanea tarda, would mobilize an administered porphyrin from tissues and enhance its excretion. Hematoporphyrin with and without chloroquine was administered to chick embryos, mice, and rats. Tissue and plasma porphyrin levels were markedly increased after hematoporphyrin dosing. Porphyrin concentrations in liver, spleen, and kidney were not significantly affected by chloroquine. Total urinary and fecal porphyrin excretion in rats treated with hematoporphyrin (50 mg/kg, i.p.) was not influenced by chloroquine treatment (100 mg/kg, s.c.). Excretion of heptacarboxylporphyrin, normally a minor fraction of urinary porphyrins, was significantly increased in chloroquine-treated rats. These results suggest that chloroquine is unlikely to be useful after photodynamic therapy for mobilizing exogenous porphyrins from tissues such as liver, spleen, and kidney. Increased urinary excretion of heptacarboxylporphyrin may contribute to the beneficial effect of chloroquine in porphyria cutanea tarda.

High-performance liquid chromatography-mass spectrometry of porphyrins by using an atmospheric pressure interface

A method is described for the high-performance liquid chromatography (HPLC) mass spectrometry analysis of porphyrin mixtures by using an atmospheric pressure interface, which can operate in two modes: pneumatically assisted elecrrospray and atmospheric pressure chemical ionization (APCI). Optimization of the conditions and evaluation of spectral information has been carried out by using direct injection of free-base and metallo porphyrin standards. The most effective results were obtained using APCI. HPLC-APCI mass spectrometry analysis of the demetallated vanadyl porphyrin fraction from the Triassic Serpiano oil shale has allowed rapid characterization of the distribution; more than 50 significant components are present. The presence of trace amounts of high molecular weight (>C33) cycloalkano porphyrins indicates the occurrence of photic zone anoxia in the ancient water column. This example illustrates the potential of the approach for studies of porphyrin mixtures of environmental or biological significance, which should be applicable to other types of metallo and free-base components that can be separated by HPLC under normal or reversed-phase conditions.

Rapid Characterization of Metallo Porphyrin Classes in Natural Extracts by Gel Permeation Chromatography/Atmospheric Pressure Chemical Ionization/Mass Spectrometry

Gel permeation chromatography/mass spectrometry with an atmospheric pressure chemical ionization interface permits the rapid characterization of the types of metallo porphyrins in sediment extracts or adsorption chromatographic fractions therefrom, even when the components are present in trace abundance and/or in much lower abundance than co-occurring components of the same polarity. Gel permeation chromatography therefore also provides a rapid means of isolating and purifying porphyrin fractions for more detailed studies of component distributions. The approach should have application for pigment analysis not only in palaeoenvironmental reconstruction and palaeoceanographic studies, but also in biological studies of porphyrins.

Novel porphyrins as molecular fossils for anoxygenic photosynthesis

The iron porphyrin fraction of Kupferschiefer, an organic-rich sedimentary rock deposited in the Zechstein Sea during the Permian (ca. 235Myr before present) contains three minor components characterised by 1H NMR spectroscopy. The carbon skeletons correlate specifically with members of one series of the bacteriochlorophylls d of the Chlorobiaceae, which are obligate anaerobes. Their structures therefore reveal the occurrence of anoxic conditions extending up into the zone of light penetration in the water column of the original depositional setting in the Lower Rhine Basin.

METALLOPETROPORPHYRINS AS PROCESS INDICATORS: MASS SPECTRAL IDENTIFICATION OF Ni(ETIO) AND Ni(DPEP) HOMOLOGOUS SERIES IN GREEN RIVER SHALE OIL

ABSTRACT Mass spectrometry (MS) of the porphyrin fraction of a demetallated shale oil from the LLNL Hot-Recycled-Solids retorting process exhibited homologous series of C25 to C33 (C28 maximum) for etio and C26 to C36 (C30 maximum) for DPEP (isocyclic) porphyrins, respectively. The sum of intensities after baseline correction yielded a ΣDPEP/Σetio ratio of 1/1. The petroporphyrin fraction was prepared by demetallation of the whole shale oil using methane sulfonic acid followed by isolation which involved extraction and purification by alumina chromatography. MS examination of silica purified fractions showed another type of homologous series, tentatively assigned as tetrahydrobenzo-DPEP por-phyrin. MS examination of porphyrin fractions isolated by alumina or alumina/silica chromatography without demetallation indicated Ni(etio) and Ni(DPEP) (isocyclic) porphyrins were observed with the same homologous series as seen in the demetallated fraction.

Correlation between levels of free and protein-bound plasma porphyrin and urinary porphyrins in porphyria cutanea tarda

Porphyria cutanea tarda (PCT) is a disorder of porphyrin metabolism that leads to massive overproduction and excretion of uroporphyrin. Most plasma porphyrins are bound to albumin and hemopexin. The aim of this work was to analyze the relationship between the concentrations of serum albumin and hemopexin, the levels of total, free and protein-bound plasma porphyrins and the urinary coproporphyrin and uroporphyrin excretion, in PCT patients at different stages of the disease. Urinary porphyrins showed a stronger correlation with total plasma porphyrin levels (r = 0.863) than with the free fraction of plasma porphyrins (r = 0.608). Patients considered in an active stage of PCT, have a higher mean level of total plasma porphyrins (8.80 micrograms/dl +/- 8.75) and a lower mean percentage of free plasma porphyrins (12.79% +/- 11.21) than those patients on remission (0.71 +/- 0.5 microgram/dl and 44.3 +/- 35.3%, respectively). 30% of patients showed hypohemopexinaemia, presumably due to hepatic damage. Despite the high affinity of this protein for porphyrins, no significant correlation was found between plasma porphyrin levels and hemopexin or albumin. It is concluded that (i) the kidney is not merely a passive filter for free plasma porphyrins and (ii) that the formation of hemopexin-porphyrin complex occurs when plasma porphyrins concentrations are increased (i.e. in those patients in an active stage of PCT).

Efficiency of three different hemodialysis membranes for plasma porphyrin removal

To assess the capability of three different membranes to remove porphyrins, plasma and dialysate porphyrin levels were fluorometrically measured in 10 patients with end-stage renal failure who were on hemodialysis. Three different hemodialysis membranes were used: cuprophan, polyacrylonitrile, and cellulose triacetate. Total plasma porphyrin concentrations decreased after dialysis, but to a lesser extent when using the cuprophan membrane (19%) than with the polyacrylonitrile (26%) or cellulose triacetate (30%) membranes (P < 0.01). However, since the free plasma porphyrin fraction remained unchanged, it can be assumed that the equilibrium between protein-bound and non-protein-bound (free) porphyrins is displaced toward the latter fraction. Dialysate porphyrin levels were lower (P < 0.01) when using the cuprophan membrane (10.1 μg/session) than when using polyacrylonitrile (17.8 μg/session) and cellulose triacetate (21.9 μg/session). Although most of the plasma porphyrins are protein bound, our results show that hemodialysis can remove significant amounts of non-protein-bound (free) porphyrins. The polyacrylonitrile and cellulose triacetate membranes had a greater capacity for porphyrin removal than cuprophan. Thus, two high-permeability membranes (polyacrylonitrile and cellulose triacetate) should be used whenever a reduction of plasma porphyrin levels is desired.

Structural identification of paramagnetic iron porphyrins from Colorado coal with the use of 1D and 2D 1H NMR spectroscopy: geochemical implications on their origin from heme

A fraction of iron porphyrins from Colorado coal constituting one major and one minor C28 isomer was analysed with the use of 1D and 2D 1H nuclear magnetic resonance spectroscopy. 2D 1H COSY and NOESY experiments in a low viscosity solvent (CD 3 OD) led to the structrural identification of the major component. Assignment of the hyperfine shifted resonances, of all the peripheral substituents on the porphyrin macrocycle, resulted in an unambiguous identification of iron(III) 2,7,12,18-tetramethyl-13,17-diethyl porphyrin. Reliability of the 2D 1H NMR method used was confirmed by analyzing a related structure, i.e. deuteroheme-IX in the same way. The minor constituent of the analysed fraction was identified by reproducing the 1H NMR spectrum with its synthetic counterpart: low-spin iron(III) 2,7,12,18-tetramethyl-3,8-diethyl porphyrin. Both identified coal iron porphyrins represent products derived from a common protoheme-IX related precursor, selectively degraded via different routes during coal diagenesis.

Temporal changes in the distribution of C 33 cycloheptenoDPEP and 17-nor C 30 DPEP in rocks

C 33 cycloheptenoDPEP is a common component in the porphyrin assemblages of certain thermally immature marine rocks. This compound is unstable and decompases on standing. 17-nor C 30DPEP, a diagenetic product of chlorophyll c, is present in minor amounts in the vanadyl porphyrin fractions of many marine sediments. It is the major porphyrin within certain sections of Monterey Formation. This unusual occurrence of a large proportion of this compound within certain sections of the Monterey Formation may indicate a change in the depositional environment, which favoured the loss of the acrylic acid chain of chlorophyll c. It may also indicate olooms of certain algge rich in chlorophyll c.

Salivary porphyrin concentration in porphyria cutanea tarda

To assess the clinical utility of saliva samples, serum, urine and saliva porphyrin concentration were fluorometrically measured in 31 patients with porphyria cutanea tarda. In comparison with normal values, porphyrin mean levels were 20-fold increased in serum and urine but only 3-fold in saliva. Saliva porphyrin concentration exhibited significant but weak correlations with porphyrin levels in serum ( r = 0.69) and urine ( r = 0.67). However, saliva porphyrins were not more closely correlated with protein-unbound serum porphyrins ( r = 0.57). This finding suggests that saliva porphyrin concentration does not simply correspond to the filtered free fraction of serum porphyrins. Nevertheless, measurement of saliva porphyrins could represent a valuable non-invasive alternative to serum porphyrins in the monitoring of patients with porphyria cutanea tarda.

Comparison of nickel and vanadyl porphyrin distributions of sediments

The distributions of nickel and vanadyl porphyrins of Toarcian shale, northern Germany, and the Monterey Formation, California, were examined. The compositions of nickel and vanadyl porphyrin fractions of extracts from the same sample show substantial differences. The nickel porphyrin distribution is more complex than the vanadyl porphyrin distribution. While the vanadyl porphyrin distributions of samples from a core are the same, their nickel porphyrin compositions show wide variations. The nickel porphyrins are enriched in “etio” and 3-nor C 30DPEP structures. The vanadyl porphyrins are enriched in the C 33DiDPEP structure. Methylpropano porphyrins are found only in the vanadyl porphyrin fraction, whereas the cycloheptano structural type is predominant in the nickel fraction. C 31DPEP and C 32DPEP are found both in the nickel and vanadyl fractions. Their relative abundance in the two fractions is proportional to the Ni VO porphyrin ratio. The observed differences in the compositions of nickel and vanadyl porphyrin fractions are due to differences in the rate constants for their formation from the pheopigments.

Experimental hepatic porphyria induced by oxadiazon in male mice and rats

Male mice and rats were fed a diet containing 1000 mg/kg of oxadiazon for 6 days. Fecal porphyrin was elevated in both mice and rats (from 30.2 to 1673.1 nmol/g dry wt and from 98.3 to 547.6 nmol/g dry wt, respectively). Porphyrin content of mouse bile was elevated from 5.7 to 439.0 nmol/g wet wt. Livers of treated animals contained mainly uroporphyrin, while protoporphyrin constituted the major porphyrin fraction in the feces of treated animals and in mouse bile. Urine of oxadiazon-treated rats contained coproporphyrin and uroporphyrin; total urine porphyrin content was 0.4 nmol/ml for control and 15.2 nmol/ml for treated rats. Porphobilinogen concentration was elevated in liver, kidneys, and blood plasma of treated animals. The activity of 5-aminolevulinic acid synthase was increased in the liver, but not in the kidneys of treated animals. Hepatic microsomal cytochrome P450 levels were decreased to about 50% of control values. The pattern of porphyrin accumulation and excretion in oxadiazon-induced experimental porphyria resembles the porphyrin pattern observed in human variegate porphyria.

Porphyrins from Messel oil shale (Eocene, Germany): Structure elucidation, geochemical and biological significance, and distribution as a function of depth

The extraction and isolation procedures of twenty nickel porphyrins (seven alkylporphyrins, thirteen carboxylic acids) from lacustrine Messel shale (Eocene, Germany), as well as the unequivocal structural assignments (obtained using 200 and 400 MHz nuclear magnetic resonance (NMR), nuclear Overhauser effect, mass spectrometry and total or partial synthesis of six reference compounds) are described. Ten porphyrins could be specifically correlated with biological precursors: algal chlorophyll c (4), bacteriochlorophylls d (3) and heme (3), while the remaining ones may arise from several chlorophylls. The structures of these fossil pigments mostly confirm the classical “Treibs scheme,” including the origin of some porphyrins from nonchlorophyll sources. They also show that, even in a very immature sediment, deep modifications occur, including, in particular, extensive degradation of chlorophyll E ring. The composition of the porphyrin fractions of Messel oil shale was also studied as a function of depth. A porphyrin acids/alkylporphyrins ratio varying from 0.35 to 24.8 demonstrated that the apparent homogeneity of the shale is not reflected on the molecular scale. This was confirmed when the abundance of the twenty individual porphyrins of known structure was measured along the core. Significant correlations between individual porphyrins were found: fossils of bacteriochlorophylls d, homolog pairs of porphyrins (3-H/3-ethyl), etc.

Structural comparison of nickel, vanadyl, copper, and free base porphyrins from Oulad Abdoun oil shale (Maastrichtian, Morocco)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural comparison of nickel, vanadyl, copper, and free base porphyrins from Oulad Abdoun oil shale (Maastrichtian, Morocco)J. Verne-Mismer, R. Ocampo, C. Bauder, H. J. Callot, and P. AlbrechtCite this: Energy Fuels 1990, 4, 6, 639–643Publication Date (Print):November 1, 1990Publication History Published online1 May 2002Published inissue 1 November 1990https://doi.org/10.1021/ef00024a003RIGHTS & PERMISSIONSArticle Views198Altmetric-Citations42LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (434 KB) Get e-Alerts Get e-Alerts

Porphyrin intercalation and non-specific ‘edge on’ outside binding to natural DNA

A theoretical two-mode binding model for porphyrin binding to natural DNA is presented. One of the binding modes is assumed to be base sequence specific with binding sites n base-pairs long. The other binding mode has binding sites which consist of only one base-pair and can involve cooperativity. The model fits satisfactorily to data for H2TMPyP-4, Cu(II)TMPyP-3 and Cu(II)TMPyP-4 binding to calf thymus DNA in both a high (mu congruent to 1.0 M) and a low (mu congruent to 0.2 M) ionic strength buffer. The results show that the fraction of porphyrin bound in the non-specific mode reaches a maximum at certain input DNA to porphyrin concentrations ratios. The value of this maximum decreased, and its position shifted to higher DNA to porphyrin concentration ratios for binding in the high ionic strength buffer. The value of the cooperativity parameter obtained through the fitting process suggests that the non-specific binding is positively cooperative. The results are compared with the data analysed using other techniques.

Preliminary characterisation of porphyrins from the Gafsa Basin, Tunisia: Evidence for metal-free benzo porphyrins from an immature sediment

Five metal-free porphyrin fractions were isolated chromatographically from an immature chert of the Gafsa Basin (Paleocene, Tunisia). Each fraction was analysed by electron ionisation tandem mass spectrometry. In addition to the expected aetioporphyrin-III and deoxophylloerythroetioporphyrin (DPEP), an isomeric C 32 CAP porphyrin, which probably bears an extended isocyclic ring was also detected. A C 31 CAP component bearing one unsubstituted β-position was isolated. C 33 and C 34 benzo-DPEP porphyrin as well as a C 33 tetrahydrobenzo-DPEP porphyrin were also present, which indicates that such compounds are generated in immature sediments.