Search results for "Protoporphyrin"

Spectral hole burning study of protoporphyrin IX substituted myoglobin.

1992

Protoporphyrin IX substituted myoglobin reveals excellent hole burning properties. We investigated the frequency shift of persistent spectral holes under isotropic pressure conditions in a range from 0 to 2.4 MPa. In this range, the protein behaves like an elastic solid. The shift of the holes under pressure shows a remarkable frequency dependence from which the compressibility of the protein can be determined. The compressibility, in turn, allows for an estimation of the equilibrium volume fluctuations. Within the frame of the model used to interpret the pressure data, it is possible to determine the absorption frequency of the isolated chromophore and the associated solvent shift in the p…

Effects of peroxidizing herbicides on protoporphyrin IX levels in non-chlorophyllous soybean cell culture

1990

Abstract The mode of action of 16 peroxidizing herbicides belonging to four different families (diphenyl ethers, oxadiazon, pyridine derivatives, and pyrazole derivatives) has been studied in nonchlorophyllous soybean cell cultures. Whenever possible, we have compared active and inactive compounds. Phytotoxic effects were estimated on the basis of growth inhibition, either in the dark or in the light. Protoporphyrin IX accumulations were estimated in dark-treated samples, using a simple methodology. In all cases, we have found a positive correlation between cellular damages and protoporphyrin IX accumulations. The results provide further evidences in favor of the light-dependent activity of…

Hole burning and pressure phenomena in chromoproteins

1993

Abstract We investigated the behavior of spectral holes under pressure at various frequencies within the inhomogeneous band for two proteins, namely myoglobin and horseradish peroxidase. In order to achieve narrow bandwidth hole burning, the heme chromophore was replaced by protoporphyrin IX and mesoporphyrin IX, respectively. In myoglobin, we found that the pressure induced shift of the holes varied in a strongly non-linear fashion, when the burn-frequency was tuned across the absorption band. In horseradish peroxidase the pressure shift was linear with burn-frequency but changed in a dramatic fashion upon complex formation with a substrate molecule. These observations are interpreted with…

X-linked protoporphyria: Iron supplementation improves protoporphyrin overload, liver damage and anaemia

2015

Synthesis and properties of a photoaffinity labeling reagent for protoporphyrinogen oxidases, the target enzymes of diphenyl ether herbicides

1994

A diazoketone 3 has been synthesized in two steps from acifluorfen 1, a diphenyl ether herbicide. Like the parent compound 1, the diazoketone 3 is toxic to plant cells and inhibits protoporphyrinogen oxidase, the molecular target of diphenyl ether herbicides. On photolysis of 3 in methanol, the generated carbene mainly undergoes the Wolff rearrangement to a ketene which further adds methanol, but many other products are observed. A tritiated derivative of 3 has been prepared which is suitable for photoaffinity labeling experiments.

With a Little Help from My Friends: The Role of Intraoperative Fluorescent Dyes in the Surgical Management of High-Grade Gliomas

2018

High-grade gliomas (HGGs) are the most frequent primary malignant brain tumors in adults, which lead to death within two years of diagnosis. Maximal safe resection of malignant gliomas as the first step of multimodal therapy is an accepted goal in malignant glioma surgery. Gross total resection has an important role in improving overall survival (OS) and progression-free survival (PFS), but identification of tumor borders is particularly difficult in HGGS. For this reason, imaging adjuncts, such as 5-aminolevulinic acid (5-ALA) or fluorescein sodium (FS) have been proposed as superior strategies for better defining the limits of surgical resection for HGG. 5-aminolevulinic acid (5-ALA) is i…

Organometallic complexes with biological molecules. I. Diorganotin(IV)chloro protoporphyrin IX complexes: Solid-state and solution-phase characteriza…

1993

Protoporphyrin IX (H4PPIX) complexes of diorganotin(IV)chloro moieties with formula (R2SnCl)2H2PPIX (RMe, Bu and Ph) have been obtained and their solid-state and solution-phase configurations have been studied through spectroscopic investigations. Coordination of the side-chain carboxylates of H4PPIX to R2Sn(IV)Cl moieties, with bridging carboxylate (COO−) has been inferred by comparison of the free and coordinated H4PPIX IR spectra, while the occurrence of a five-coordinated tin(IV) atom in a cis-R2 trigonal bipyramidal structure has been deduced, for all of the synthesized complexes, by rationalization of the nuclear quadrupole splitting parameters, according to the point-charge model for…

Thermal broadening of the Soret band in heme complexes and in heme-proteins: role of iron dynamics

1994

We report the thermal broadening of the Soret band in heme-CO, heme-OH and protoporphyrin IX in the temperature range 300-20 K. For protoporphyrin IX the temperature dependent Gaussian line broadening follows the behavior predicted by the harmonic approximation in the entire temperature range investigated. In contrast, for heme-CO and heme-OH the harmonic behavior is obeyed only up to about 180 K and an anomalous line broadening increase is observed at higher temperatures. This effect is attributed to the onset of anharmonic motions of the iron atom with respect to the porphyrin plane. Comparison with previously reported analogous data for heme proteins enables us to suggest that the onset …

Characterization of (3H) acifluorfen binding to purified pea etioplasts, and evidence that protoporphyrinogen oxidase specifically binds acifluorfen

1992

It is now generally accepted that protoporphyrinogen oxidase is the target-enzyme for diphenylether-type herbicides. Recent studies [Camadro, J-M., Matringe, M., Scalla, R. & Labbe, P. (1991) Biochem. J. 277, 17–21] have revealed that in maize, diphenyl ethers competitively inhibit protoporphyrinogen oxidase with respect to its substrate, protoporphyrinogen IX. In this study, we show that, in purified pea etioplast, [3H]acifluorfen specifically binds to a single class of high-affinity binding sites with an apparent dissociation constant of 6.2 ± 1.3 nM and a maximum density of 29 ± 5 nmol/g protein. [3H]Acifluorfen binding reaches equilibrium in about 1 min at 30°C. Half dissociation occurs…

Hemin-coupled iron(III)-hydroxide nanoparticles show increased uptake in Caco-2 cells

2011

Abstract Objectives The absorption of commonly used ferrous iron salts from intestinal segments at neutral to slightly alkaline pH is low, mainly because soluble ferrous iron is easily oxidized to poorly soluble ferric iron and ferrous iron but not ferric iron is carried by the divalent metal transporter DMT-1. Moreover, ferrous iron frequently causes gastrointestinal side effects. In iron(III)-hydroxide nanoparticles hundreds of ferric iron atoms are safely packed in nanoscaled cores surrounded by a solubilising carbohydrate shell, yet bioavailability from such particles is insufficient when compared with ferrous salts. To increase their intestinal uptake iron(III)-hydroxide nanoparticles …