Showing papers on "Protoporphyrin IX published in 1987"

An HPLC assay for rat liver ferrochelatase activity.

Abstract: A rapid, reliable, sensitive and reproducible HPLC method was developed for the assay of ferrochelatase activity in rat liver. The assay was carried out aerobically with Zn2+ and mesoporphyrin or protoporphyrin IX as substrates. Zn-porphyrins formed were extracted with dimethyl sulphoxide/methanol (30:70, v/v) containing Zn-deuteroporphyrin as the internal standard for separation and quantification by reversed-phase chromatography. The Km for mesoporphyrin was 5.9 microM, for protoporphyrin IX 8.8 microM and for zinc 6.0 microM. The specific activities were 33.1 +/- 5.0 nmol Zn-mesoporphyrin or 13.4 +/- 2.0 nmol Zn-protoporphyrin formed per hour per mg of protein for mitochondria and 12.3 +/- 2.2 nmol Zn-mesoporphyrin or 4.6 +/- 0.9 nmol Zn-protoporphyrin per hour per mg of protein for liver homogenate.

Uptake of protoporphyrin and violet light photodestruction of propionibacterium acnes

Abstract: The uptake of protoporphyrin IX by Propionibacterium acnes in suspension has been studied by fluorescence spectroscopy. Protoporphyrin, after it was injected into a cell suspension, was firstly bound to receptors on the cell surface and in this state protoporphyrin was non-fluorescent. Subsequently, probably as a result of lateral diffusion in the cell wall, these protoporphyrin-receptor complexes formed dimers. The final step in the overall uptake process of protoporphyrin by the cells from the surroundings consisted in a jump of such dimers from waterlike to lipidlike compartments in the cell membrane where protoporphyrin became fluorescent. The lipidlike compartments in the cells had a limited binding capacity of protoporphyrin. The fraction of surviving cells versus light dose has also been studied for varying amounts of protoporphyrin added to the cell suspensions. The survival curves were exponentially decaying with the irradiation time and there was a direct proportionality between the inverse slope of the survival curves and the intensity of protoporphyrin fluorescence form the lipidlike compartments. The relevance of these results to the therapy of Acne vulgaris is also discussed.

An h.p.l.c. assay for protoporphyrinogen oxidase activity in rat liver.

Abstract: An h.p.l.c. method is described for the assay of protoporphyrinogen oxidase activity in rat liver. A relatively pure protoporphyrinogen IX substrate was obtained by selectively removing any protoporphyrin IX unreduced by sodium amalgam on a small disposable cartridge packed with a strong anion-exchanger. The protoporphyrin IX formed was extracted with dimethyl sulphoxide/methanol (3:7, v/v) containing mesoporphyrin as the internal standard for separation and quantification by reversed-phase chromatography. The Km for protoporphyrinogen was 9.5 +/- 1.6 microM, and the enzyme activities were 0.59 +/- 0.11 nmol of protoporphyrin IX produced/min per mg of mitochondrial protein and 33.5 +/- 2.7 nmol protoporphyrin IX produced/min per g of liver tissue homogenate. The method is applicable to the determination of enzyme activity in small amounts of human liver biopsy.

Isolation of human ferrochelatase.

Abstract: To the Editor.— Ferrochelatase (protoheme ferrolyase, EC 4.99.1.1) catalyzes the insertion of ferrous iron into protoporphyrin IX to form protoheme. Reduced activity of this enzyme is found in the human disease erythropoietic protoporphyria, which is characterized by high levels of protoporphyrin in blood, stool, and skin, and extreme sensitivity to visible light. 1 Although treatment with β-carotene relieves photosensitivity in the majority of patients, 1 it has no effect on the abnormal accumulation of protoporphyrin. Purification of human ferrochelatase is the necessary first step in studies of thegenetic defect of this disease. Ferrochelatase has been isolated from rat and beef liver and chicken erythrocytes. 2-5 We report here that we have been able to isolate ferrochelatase from human liver obtained at autopsy, using the methods published for the isolation of rat liver ferrochelatase. 2 Table 1 summarizes the purification scheme. The yields and purity of the enzyme are similar

Inhibition of ferrochelatase during differentiation of murine erythroleukaemia cells.

Abstract: During dimethyl sulphoxide-induced differentiation of DS-19 murine erythroleukaemia (MEL) cells, the activity of the terminal enzyme of the haem-biosynthetic pathway, ferrochelatase (protohaem ferrolyase, EC 4.99.1.1), is thought to be the rate-limiting step for haem production. Differentiation of induced MEL cells in the presence of exogeneously supplied protoporphyrin IX showed that total haem production was affected by added porphyrin only after 48 h. These data suggest that iron insertion, the terminal step, is rate-limiting during the first 48 h of differentiation. Addition of low levels of diethoxycarbonyl-1,4-dihydro-2,4,6-trimethylpyridine to differentiating cultures resulted in decreased haem production and decreased ferrochelatase activity. N-Methylprotoporphyrin at nanomolar concentrations also strongly inhibited ferrochelatase activity, but had no inhibitory effect on cellular haem production. The bivalent cations Co2+, Cd2+ and Mn2+ were tested for their effect on haem production and ferrochelatase activity. All three metals were found to inhibit both haem formation and ferrochelatase activity, with Mn2+ being the strongest effector. These data, together with those previously published, suggest that the terminal step in haem biosynthesis is rate-limiting during the early stages of differentiation in MEL cells.

Fluctuation domains in myoglobin. Fluorescence quenching studies.

Abstract: The dynamics of two domains in the myoglobin molecule, close to the heme and inside the protein medium including the surface, are investigated through the study of the fluorescence oxygen quenching of two probes imbedded in the heme pocket: zinc protoporphyrin IX (with a fluorescence lifetime of 2.1 ns) and metal-free protoporphyrin IX (with a fluorescence lifetime of 17.8 ns).

Influence of heme-surrounding amino acid residues on the manganese (V)-nitrido bond in manganese-substituted hemoproteins: resonance Raman evidence for porphyrin core expansion and reduction of the manganese(V)-nitrido stretching force constant.

Abstract: Nitridomanganese(V) protoporphyrin IX was prepared by hypochlorite oxidation of the corresponding manganese(III) protoporphyrin IX derivative in the presence of ammonium ion and by photolysis of the corresponding azidomanganese(III) complex. Myoglobin and horseradish peroxidase containing this novel protoporphyrin derivative were prepared for the first time. These remarkably stable species were examined by electronic absorption, electron paramagnetic resonance, and resonance Raman spectroscopies. The MnV-N stretching modes of the nitridomanganese(V)-substituted myoglobin and horseradish peroxidase were observed at 1010 and 1003 cm-1, respectively, by resonance Raman spectroscopy, while the MnV-N stretching frequency for nitridomanganese(V) protoporphyrin IX in 0.1 N aqueous NaOH was found at 1046 cm-1. The equilibrium dissociation energies of MnV-N bonds in these complexes were estimated from vibrational overtone spacings by introducing the Morse potential energy function, were found to be around 4.5 eV, and seemed independent of the surroundings of the manganese porphyrin, although its force constant decreased from 7.3 to 6.7 mdyn/A upon incorporation into apoprotein. The porphyrin ring modes of these nitridomanganese(V) derivatives were influenced greatly upon incorporation into apoproteins, suggestive of the occurrence of porphyrin core expansion. Upon this core expansion the MnV center moves into the mean plane of porphyrin plane, but the access of nitrido (N) toward MnV is restricted due to a steric hindrance from porphyrin pyrrole nitrogens. The resulting stretched MnV-N bond might cause lowering of the MnV-N stretching frequency upon incorporation into apoprotein.

Drug for suppressing hepatopathy

Abstract: PURPOSE: To obtain a hepatopathy-suppressing drug for oral administration exhibiting excellent effect in improving hepatic function and suppressing hepatopathy, by using a protoporphyrin IX zinc(II) complex as an active component. CONSTITUTION: The objective drug can be produced by mixing a protoporphyrin IX zinc(II) complex with conventional drug additives and forming the mixture in the form of a drug by conventional method. It can be used in the form of powder, tablet, pill, capsule, granule, suspension, etc. It is administered at a dose of 10mg W several g, preferably 10mgW1g daily. If necessary, the agent can be used in combination with other drugs. protoporphyrin IX zinc(II) complex can be easily produced from protoporphyrin IX by known process. The compound suppresses the increase of GPT and GOT in serum and the increase of the weight of liver. COPYRIGHT: (C)1988,JPO&Japio

Enhanced stability of the oxygen complex of Co(II) protoporphyrin IX upon its association with cyclodextrins

Abstract: 1. Co-Protoporphyrin forms a pentacoordinated complex with imidazole which binds O2 in DMF solution. 2. Upon association with cyclodextrin, the resistance of the O2CoPP-imidazole complex toward autoxidation is markedly enhanced.