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Showing papers on "Protoporphyrin IX published in 1991"


Journal ArticleDOI
TL;DR: Differential susceptibility to acifluorfen of the species examined in this study appears to be due in large part to differences in Proto IX accumulation in response to the herbicide, in some cases, due to Differences in activity of the porphyrin pathway.
Abstract: With a leaf disc assay, 11 species were tested for effects of the herbicide acifluorfen on porphyrin accumulation in darkness and subsequent electrolyte leakage and photobleaching of chlorophyll after exposure to light. Protoporphyrin IX (Proto IX) was the only porphyrin that was substantially increased by the herbicide in any of the species. However, there was a wide range in the amount of Proto IX accumulation caused by 0.1 millimolar acifluorfen between species. Within species, there was a reduced effect of the herbicide in older tissues. Therefore, direct quantitative comparisons between species are difficult. Nevertheless, when data from different species and from tissues of different age within a species were plotted, there was a curvilinear relationship between the amount of Proto IX caused to accumulate during 20 hours of darkness and the amount of electrolyte leakage or chlorophyll photobleaching caused after 6 and 24 hours of light, respectively, following the dark period. Herbicidal damage plateaued at about 10 nanomoles of Proto IX per gram of fresh weight. Little difference was found between in vitro acifluorfen inhibition of protoporphyrinogen oxidase (Protox) of plastid preparations of mustard, cucumber, and morning glory, three species with large differences in their susceptibility at the tissue level. Mustard, a highly tolerant species, produced little Proto IX in response to the herbicide, despite having a highly susceptible Protox. Acifluorfen blocked carbon flow from δ-aminolevulinic acid to protochlorophyllide in mustard, indicating that it inhibits Protox in vivo. Increasing δ-aminolevulinic acid concentrations (33-333 micromolar) supplied to mustard with 0.1 millimolar acifluorfen increased Proto IX accumulation and herbicidal activity, demonstrating that mustard sensitivity to Proto IX was similar to other species. Differential susceptibility to acifluorfen of the species examined in this study appears to be due in large part to differences in Proto IX accumulation in response to the herbicide. In some cases, differences in Proto IX accumulation appear to be due to differences in activity of the porphyrin pathway.

98 citations


Journal ArticleDOI
TL;DR: In this report, an in vitro assay for Mg-chelatase is described and it is suggested that the cucumber pellet was the component that lost activity during lysis, and broken and reconstituted cucumber chloroplasts were unable to maintain M g-Chelatase activity.
Abstract: The first committed step in chlorophyll synthesis is the Mg-chelatase-catalyzed insertion of magnesium into protoporphyrin IX. Since iron insertion into protoporphyrin leads to heme formation, Mg-chelastase lies at the branch point of heme and chlorophyll synthesis in chloroplasts. Little is known about the enzymology or regulation of Mg-chelatase, as it has been assayed only in intact cucumber chloroplasts. In this report we describe an in vitro assay for Mg-chelatase. Mg-chelatase activity in intact pea chloroplasts was 3- to 4-fold higher than in cucumber chloroplasts. This activity survived chloroplast lysis and could be fractionated by centrifugation into supernatant and pellet components. Both of these fractions were required to reconstitute Mg-chelatase activity, and both were inactivated by boiling indicating that the enzyme is composed of soluble and membrane-bound protein(s). The product of the reaction was confirmed fluorometrically as the magnesium chelate of the porphyrin substrate. The specific activity of the reconstituted system was typically 1 nmol of Mg-deuteroporphyrin per h per mg of protein, and activity was linear for at least 60 min under our assay conditions. ATP and magnesium were required for Mg-chelatase activity and the enzyme was sensitive to the sulfhydryl reagent N-ethylmaleimide (I50, 20 microM). Broken and reconstituted cucumber chloroplasts were unable to maintain Mg-chelatase activity. However, the cucumber supernatant fraction was active when combined with the pellet fraction of peas; the converse was not true, which suggested that the cucumber pellet was the component that lost activity during lysis.

94 citations


Journal ArticleDOI
TL;DR: The results suggest that the induction of heme oxygenase by phenylhydrazine and the diamide is preceded by an oxidative stress which very likely originates in the depletion of GSH.

84 citations


Journal ArticleDOI
TL;DR: Mg-chelatase catalyzes the first step unique to the chlorophyll branch of tetrapyrrole biosynthesis, namely the insertion of Mg into protoporphyrin IX (Proto) in intact chloroplasts from semi-green cucumber cotyledons.
Abstract: Mg-chelatase catalyzes the first step unique to the chlorophyll branch of tetrapyrrole biosynthesis, namely the insertion of Mg into protoporphyrin IX (Proto). Mg-chelatase was assayed in intact chloroplasts from semi-green cucumber (Cucumis sativus, cv Sumter) cotyledons. In the presence of Proto and MgATP, enzyme activity was linear for 50 minutes. Plastid intactness was directly related to (and necessary for) Mg-chelatase activity. Uncouplers and ionophores did not inhibit Mg-Chelatase in the presence of ATP. The nonhydrolyzable ATP analogs, beta,gamma-methylene ATP and adenylylimidodiphosphate, could not sustain Mg-chelatase activity alone and were inhibitory in the presence of ATP (I(50) 10 and 3 millimolar, respectively). Mg-chelatase was also inhibited by N-ethylmaleimide (I(50), 50 micromolar) and the metal ion chelators 2,2'-dipyridyl and 1, 10 phenanthroline (but not to the same degree by their nonchelating analogs). In addition to Proto, the following porphyrins acted as Mg-chelatase substrates, giving comparable specific activities: deuteroporphyrin, mesoporphyrin, 2-ethyl, 4-vinyl Proto and 2-vinyl, 4-ethyl Proto. Mg-chelatase activity and freely exchangeable heme levels increased steadily with greening, reaching a maximum and leveling off after 15 hours in the light. Exogenous protochlorophyllide, chlorophyllide, heme, and Mg-Proto had no measurable effect on Mg-chelatase activity. The potent ferrochelatase inhibitors, N-methylmesoporphyrin and N-methylprotoporphyrin, inhibited Mg-chelatase at micromolar concentrations.

84 citations


Journal ArticleDOI
TL;DR: It is confirmed genetically that the visA gene is a structural gene for ferrochelatase (protoheme ferro-lyase, EC 4.99.1.1), and the light-induced cell death appears to be brought about by the accumulation of protoporphyrin IX, one of the substrates of ferroChelatase.
Abstract: Mutations in the visA gene of Escherichia coli cause the mutant bacteria to die upon illumination with visible light. We confirmed genetically that the visA gene is a structural gene for ferrochelatase (protoheme ferro-lyase, EC 4.99.1.1). Since other mutations in the genes involved in the biosynthesis of heme can cure the photosensitivity, the light-induced cell death appears to be brought about by the accumulation of protoporphyrin IX, one of the substrates of ferrochelatase. When cells are illuminated with visible light, protoporphyrin IX seems to produce an active species of oxygen (probably 1O2) that is harmful to the cells. This defect is the same as that associated with the human disease protoporphyria.

77 citations


Journal ArticleDOI
TL;DR: A mechanism for inducing feedback inhibition of the tetrapyrrole pathway exists in human erythroid cells and regulates heme biosynthesis by limiting the availability of the porphyrin, rather than the metal substrate for the ferrochelatase reaction.

44 citations


Journal ArticleDOI
TL;DR: The association behavior of protoporphyrin IX was investigated at different pH by absorption spectroscopy and gel chromatography as mentioned in this paper, and it was shown that poly(n-vinylpyrrolidone) tended to suppress dimerization and aggregation of the protein.
Abstract: The association behavior of protoporphyrin IX was investigated at different pH by absorption spectroscopy and gel chromatography. Protoporphyrin IX existed as monomer in acidic water, as aggregate in neutral water, and as dimer in basic water. Poly(N-vinylpyrrolidone) tended to suppress dimerization and aggregation of protopophyrin IX.

42 citations


Patent
23 Dec 1991
TL;DR: In this article, a method and a pharmaceutical composition for killing mammalian tumor cells by subjecting said cells to light in the presence of a light-activatable tetrapyrrole was presented.
Abstract: Disclosed is a method and a pharmaceutical composition for killing mammalian tumor cells by subjecting said cells to light in the presence of a light-activatable tetrapyrrole, in which the improvement comprises treating said cells with a compound which inhibits the enzymatic conversion of protoporphyrinogen to protoporphyrin IX by protoporphyrinogen oxidase in said cells thereby causing a buildup of protoporphyrin IX in said cells. Also disclosed is a method for the production of protoporphyrin IX which comprises growing eukaryotic microalgae in the presence of a protoporphyrinogen oxidase inhibitor.

41 citations


Journal ArticleDOI
TL;DR: Rapid, sensitive and specific high-performance liquid chromatographic assays are described for protoporphyrinogen oxidase and ferrochelatase in human leucocytes in humans with variegate porphyria.

30 citations


Journal ArticleDOI
Nobuaki Mito1, R. Sato1, Masakazu Miyakado1, Hiromichi Oshio1, Shizuya Tanaka1 
TL;DR: The effect of N-Phenylimide photobleaching herbicides on in vitro synthesis of protoporphyrin was examined in this article, and the binding site affinity was 8.9 − 9.8 nM.

23 citations


Journal ArticleDOI
TL;DR: A hepatic green pigment with inhibitory properties towards the enzyme ferrochelatase has been isolated from the liver of mice treated with griseofulvin and identified as N-methylprotoporphyrin, and the fragmentation of this adduct in tandem m.s.s suggests that griseefulvin is bound to the pyrrole nitrogen through one of its carbon atoms.
Abstract: 1. A hepatic green pigment with inhibitory properties towards the enzyme ferrochelatase has been isolated from the liver of mice treated with griseofulvin and identified as N-methylprotoporphyrin. 2. All four structural isomers of N-methylprotoporphyrin have been demonstrated to be present, NA, where ring A of protoporphyrin IX is N-methylated, being the predominant isomer. 3. In addition to N-methylprotoporphyrin, a second green pigment, present in far greater amounts, was also isolated from the liver of griseofulvin-treated mice. This second green pigment is also an N-monosubstituted protoporphyrin, but in this case the substituent on the pyrrole nitrogen atom appears to be intact griseofulvin rather than a methyl group. 4. The fragmentation of this adduct in tandem m.s. studies suggests that griseofulvin is bound to the pyrrole nitrogen through one of its carbon atoms and further suggests that N-methylprotoporphyrin may arise as a secondary product from the major griseofulvin pigment.

Journal ArticleDOI
TL;DR: A relationship is revealed between conformational states of the heme crevice and the N-terminal part of apo-Mb and the quenching is evidently dynamic because the fluorescence lifetime is shown to be linearly proportional to quantum yield in this pH range.
Abstract: The porphyrin and tryptophan fluorescence of sperm whale apomyoglobin complexed with protoporphyrin IX has been studied in the pH range 2-13. It has been shown that the fluorescence and absorption spectra of protoporphyrin incorporated into the heme crevice remain constant in the pH range 5.5-10.8 but change significantly at pH less than 5.5 and pH greater than 10.8, due to the acid and alkaline denaturation, respectively, of the complex accompanied by dissociation of protoporphyrin IX. At the same pH ranges, the quantum yield of tryptophanyl fluorescence increases sharply as a result of removal of protoporphyrin, acting as a quencher, from the complex. Other parameters of tryptophanyl fluorescence (maximum position, halfwidth and spectrum shape) change in the alkaline region as well. In the acidic pH range, these parameters change only at pH less than 4.3, indicating that the Trp surroundings are more stable to denaturation than the heme crevice region. Between pH 5.5 and 10.9, where the complex of apomyoglobin with protoporphyrin IX is in its native state, the main parameters of tryptophan fluorescence remain unchanged except for the ratio I325/I350 which diminishes at pH greater than 9.5. Its alteration precedes the alkaline denaturation of the complex and can be explained by a local conformational change induced by the break of the 'salt bridges' essential for the maintenance of the native Mb structure in the N-terminal region. The fluorescence data obtained for apomyoglobin, myoglobin and the complex between protoporphyrin IX and apomyoglobin enable one to compare their structures and to evaluate the role of the porphyrin macrocycle and the iron atom in the formation of the native myoglobin structure and its functioning.

Journal ArticleDOI
TL;DR: In this paper, it was shown that continuous illumination is mandatory for the induction of tetrapyrrole accumulation in acifluen-sodium-treated plants and for the photosensitization of tetraphyrrole-dependent photodynamic damage.
Abstract: It is shown that continuous illumination is mandatory for the induction of tetrapyrrole accumulation in acifluorfen-sodium-treated plants and for the photosensitization of tetrapyrrole-dependent photodynamic damage. At low concentrations of acifluorfen-sodium (up to 20 μM), photoporphyrin IX appears to be the major light-induced tetrapyrrole that accumulates in the treated plants. At higher concentrations of acifluorfen-sodium, monovinyl chlorophyllide a accumulates in addition to protoporphyrin IX. In the light, the development of photodynamic injury appears to be directly related to the accumulation of the light-induced tetrapyrroles. For example when acifluorfen-sodium-treated plants are returned to darkness, or are treated with tetrapyrrole biosynthesis inhibitors, tetrapyrrole accumulation and photodynamic injury come to a halt. In-vivo and in-organello studies failed, however, to support the commonly held hypothesis that the induction of tetrapyrrole accumulation in the light, in acifluorfen-sodium-treated plants, is only dependent on the inhibition of protoporphyrinogen oxidase. Indeed, when plastids capable of very high rates of tetrapyrrole biosynthesis and accumulation were incubated with δ-aminolevulinic acid and acifluorfen-sodium, either in darkness or in the light, a severe inhibition of protoporphyrin IX and total terapyrrole formation was observed. Althoung these results are compatible with the inhibition of tetrapyrrole formation by acifluorfensodium at the level of protoporphyrinogen oxidase, they indicate that, in addition to that inhibition, other cuellular processes are probably involved in the light-dependent accumulation of protoporphyrin IX in acifluorfensodium-treated plants.

Journal ArticleDOI
TL;DR: The SnPP complex with equine myoglobin (EqMb) is studied by 1H and 119Sn nuclear magnetic resonance spectroscopy as a general model for SnPP interaction with hemoproteins to demonstrate that the proximal His93F8-metal coordination is likely to be intact in SnPP.

Journal ArticleDOI
TL;DR: Results clearly show that the administered PP is distributed in the liver and inhibits the lipid peroxidation in vivo.
Abstract: Effect of intravenous administration of protoporphyrin IX (PP) on lipid peroxidation was studied in rats. PP and/or PP-derived porphyrins were found to be mainly distributed in livers, spleen and lungs. Dose-dependent decreases in the Fe2+ and L-ascorbic acid-stimulated lipid peroxidation in homogenates of livers and dose-dependent increases in porphyrin concentration in livers were observed after the PP injection. In the experiments with a 20 mg/kg dose of PP, the peroxidation level in the liver homogenates reached its minimum level during the period of 3 to 24 h accompanying the high porphyrin concentration in livers after the administration. After 96 h, a relatively high porphyrin concentration was still retained, but decreases in the peroxidation levels had ceased. PP administration caused a dose-dependent decrease in the endogenous lipid peroxides in livers within 0.5 h and the low levels were maintained throughout the course of the 168-h study. These results clearly show that the administered PP is distributed in the liver and inhibits the lipid peroxidation in vivo.

Journal ArticleDOI
TL;DR: Findings indicate that endogenous porphyrins, presumably acting through the mitochondrial benzodiazepine receptor, could regulate the proliferation of mouse spleen lymphocytes in vitro.

Journal ArticleDOI
TL;DR: The results suggest that S-23142 and acifluorfenethyl enhance the accumulation of protoporphyrin IX, which forms the complex with the membrane protein.
Abstract: Porphyrin accumulation in excised cucumber cotyledons (Cucumis sativus L) treated with a N-phenylimide S-23142 (N-[4-chloro-2-fluoro-5-propargyloxyphenyl]-3,4,5,6- tetrahydrophthalimide) and a diphenylether acifluorfen-ethyl (ethyl-5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitro benzoic acid) was studied Most of the accumulated porphyrins were found in the membrane fractions of 6,000g and 30,000g pellets, forming a complex with a membrane polypeptide The complex was solubilized with 1% n-dodecyl β-d-maltoside and its molecular mass was estimated to be 63,000 and 66,000 daltons by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel permeation high performance liquid chromatography (HPLC), respectively The polypeptide also existed in untreated cotyledons but had little protoporphyrin IX The complex was also formed in vitro by mixing the 30,000g pellets from untreated cotyledons and authentic protoporphyrin IX However, protoporphyrin IX formed the complex specifically with the 63,000 dalton polypeptide and not with the other proteins both in vivo and in vitro At least four fluorescent porphyrins, including protoporphyrin IX, were found in the acetone extract of the cotyledons by HPLC using a reversed phase column Protoporphyrin IX was one of the two porphyrins that formed the complex These results suggest that S-23142 and acifluorfenethyl enhance the accumulation of protoporphyrin IX, which forms the complex with the membrane protein

Journal ArticleDOI
TL;DR: In this paper, the isomerically pure isomer which was converted into magnesium(II) 2,4-divinylpheoporphyrin a53 in the absence of the SAM cofactor was identified as the physiologically significant 6-methyl ester 2.
Abstract: Treatment of 2,4-diacetyldeuteroporphyrin IX with oxalyl dichloride and t-butyl alcohol gives mainly the two isomeric mono-t-butyl esters, 10 and 11, which can be separated by thick-layer chromatography on silica gel. These monoesters can be individually transformed, via a sequence of steps, into the corresponding isomerically pure protoporphyrin IX monomethyl esters, 5 and 6, one being the magnesium (II)-free derivative of a key intermediate in the biosynthetic pathway to chlorophylls and bacteriochlorophylls. The isomerically pure monomethyl esters 5 and 6 were magnesiated and the resulting magnesium(II) protoporphyrin IX monomethyl esters 2 and 4, respectively, were challenged with a suspension of isolated developing chloroplasts in the presence and absence of added S-adenosylmethionine. The isomerically pure isomer which was converted into magnesium(II) 2,4-divinylpheoporphyrin a53 in the absence of the SAM cofactor was identified as the physiologically significant 6-methyl ester 2.

Patent
28 Oct 1991
TL;DR: In this article, a method of detecting and treating malignant and nonmalignant tissue abnormalities and lesions of the skin, conjunctives, respiratory, digestive and vaginal mucosa; endometrium and urothelium was proposed.
Abstract: A method of detecting and treating malignant and nonmalignant tissue abnormalities and lesions of the skin, conjunctives, respiratory, digestive and vaginal mucosa; endometrium and urothelium in which 5-aminolevulinic acid is administered to the patient in an amount sufficient to induce synthesis of protoporphyrin IX in the lesions, followed by exposure of the treated lesion to a photoactivating light in the range 350-640 nm

Journal ArticleDOI
TL;DR: The results demonstrate a dramatic increase in oxygen accessibility to the naphthalene probes compared to protoporphyrin IX, which can be correlated to the increased stability of the protein-protoporphyr in IX complex.

Proceedings ArticleDOI
01 Nov 1991
TL;DR: Human skin shows a strong autofluorescence in the red spectral region caused on the porphyrin production of the Gram positive lipophile skin bacterium Propionibacterium acnes, but the photodynamic activity of these photoproducts determined by scattering measurements on human erythrocytes is lower than that of protoporphyr in IX.
Abstract: Human skin shows a strong autofluorescence in the red spectral region caused on the porphyrin production of the Gram positive lipophile skin bacterium Propionibacterium acnes. Irradiation of these bacteria reduces the integral fluorescence intensity and induces the formation of fluorescent photoproducts. The fluorescence band at around 670 nm and the decay times of around 1 ns and 5 ns are typical for protoporphyrin products. The photoproduct formation is connected with an increased absorption in the red spectral region. However the photodynamic activity of these photoproducts determined by scattering measurements on human erythrocytes is lower than that of protoporphyrin IX. 1:

Journal ArticleDOI
TL;DR: Data suggest that Proto IX is the principal compound responsible for the rapid electrolyte leakage from plants, and that variation in the herbicidal activity of the diphenyl ethers observed in the study is caused by differential activity in accumulation of Proto IX.
Abstract: The relationship between protoporphyrin IX (Proto IX) levels and herbicidal activity of diphenyl ether herbicides in intact higher plant Lemna paucicostata Hegelm. strain 441 was determined. Rapid accumulation of Proto IX in the plant was observed after simultaneous exposure to light and oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl) benzene]. At 4hr, the accumulation reached the maximum and this was followed by a rapid decrease. The rate of decrease was slowed when the plants were transferred to darkness after 4hr light irradiation, although some Proto IX degradation continued in the dark. This suggests that not only photo-decomposition but degradation and/or metabolism which occurred in darkness are involved in the decrease. Proto IX levels accumulated in the plants and electrolyte leakage from the plants were increased with increasing concentration of oxyfluorfen. A positive correlation was found between Proto IX content and electrolyte leakage. Diphenyl ether herbicides used in the study had differential activity in the accumulation of Proto IX. A positive correlation was also found between Proto IX levels and their herbicidal activity to the plant.These data suggest that Proto IX is the principal compound responsible for the rapid electrolyte leakage from plants, and that variation in the herbicidal activity of the diphenyl ethers observed in the study is caused by differential activity in accumulation of Proto IX.

Journal ArticleDOI
TL;DR: In this article, the isomerically pure isomer which was converted into magnesium(II) 2,4-divinylpheoporphyrin a53 in the absence of the SAM cofactor was identified as the physiologically significant 6-methyl ester 2.
Abstract: Treatment of 2,4-diacetyldeuteroporphyrin IX with oxalyl dichloride and t-butyl alcohol gives mainly the two isomeric mono-t-butyl esters, 10 and 11, which can be separated by thick-layer chromatography on silica gel. These monoesters can be individually transformed, via a sequence of steps, into the corresponding isomerically pure protoporphyrin IX monomethyl esters, 5 and 6, one being the magnesium (II)-free derivative of a key intermediate in the biosynthetic pathway to chlorophylls and bacteriochlorophylls. The isomerically pure monomethyl esters 5 and 6 were magnesiated and the resulting magnesium(II) protoporphyrin IX monomethyl esters 2 and 4, respectively, were challenged with a suspension of isolated developing chloroplasts in the presence and absence of added S-adenosylmethionine. The isomerically pure isomer which was converted into magnesium(II) 2,4-divinylpheoporphyrin a53 in the absence of the SAM cofactor was identified as the physiologically significant 6-methyl ester 2.