The Thermodynamic Stability of Porphyrinogens

Mauzerall, D.

doi:10.1021/ja01495a052

Cited by 144 publications

(50 citation statements)

References 2 publications

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“…Since 1960 [1,2], porphyrinogens have been extensively used for a variety of applications involving their properties as complexing agents, such as chelating agents for anions [3,4], neutral molecules [5], host materials for inclusion crystals [6] and metal ion complexation [7]. Nevertheless, the need for the development of further applications of these macrocycles has been stressed in a recent publication entitled ''Calix [4]pyrrole: An Old yet New Ion-Pair Receptor'' [8].…”

Section: Introductionmentioning

confidence: 99%

Transport of solutes through calix[4]pyrrole-containing cellulose acetate films

Valente

Jiménez

Simões

et al. 2007

European Polymer Journal

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Films of cellulose acetate containing different concentrations of meso-octamethyl-porphyrinogen (calix[4]pyrrole) were prepared and characterized using UV-vis and FTIR spectroscopy, DSC and SEM. Incorporation of calix[4]pyrrole into cellulose acetate leads to a decrease in the degree of hydrophilicity of the polymeric matrix. However, a slight increase in the percentage of water uptake of the polymer is found with an increase of the initial amount of calix [4]pyrrole in the composite composition. This effect can be related to the plasticizing effect that the calix[4]pyrrole provokes in the cellulose acetate. A comparative study of transport parameters of oxygen and some non-associated electrolytes (sodium, copper(II) and nickel chlorides) was carried out. The diffusion coefficients of molecular oxygen through cellulose acetate films decrease with an increase of the concentration of calix [4]pyrrole in the composite films. The transport (diffusion and permeation) of the above mentioned electrolytes through a set of composite films shows a decrease of permeability and diffusion coefficients with an increase of calix[4]pyrrole concentration. Such behaviour is typical of systems where interactions between the polymer and diffusing species occur. However, from the analysis of the distribution coefficient, it was found that those interactions are only dependent on the calix[4]pyrrole content for 2:1 electrolytes.

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Section: Introductionmentioning

confidence: 99%

Transport of solutes through calix[4]pyrrole-containing cellulose acetate films

Valente

Jiménez

Simões

et al. 2007

European Polymer Journal

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“…The sampling procedure for urinary coproporphyrins was started with an oxidation step to prevent possible non-enzymatic isomerization of porphyrinogens under relatively acidic conditions (17,21). The resulting porphyrins, however, are absolutely stable to further isomerization (21).…”

Section: Resultsmentioning

confidence: 99%

Composition of Urinary Coproporphyrin Isomers I — IV in Human Porphyrias

Jacob¹,

Doss²

1993

Clinical Chemistry and Laboratory Medicine

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Summary:The urinary distribution and relative proportions of the four Coproporphyrin isomers I-IV were investigated in 50 patients suffering from hepatic and erythropoietic types of hereditary porphyrias. A highly efficient sample preparation method was applied to isolate urinary coproporphyrins, the isomer ratios of which were quantitated by isocratic ion-pair high-performance liquid chromatography. Results showed a significant decrease (p < 0.001) of the proportion of Coproporphyrin I in acute hepatic porphyria (acute intermittent porphyria, hereditary coproporphyria, variegate porphyria, porphobilinogen synthase deficiency porphyria) as compared with chronic hepatic porphyria (porphyria cutanea tarda, chronic hepatic porphyria type B and C) (13.2 ± 5.3%, χ ± S.D., vs. 31.4 ± 11.5%). Conversely, the proportion of isomer III was significantly higher (p < 0.001) in acute hepatic porphyria than in chronic hepatic porphyria (80.9 + 5.2% vs. 62.2 + 10.9%). As expected, the highest level of Coproporphyrin I (90.0 ± 1.9%) was found in congenital erythropoietic porphyria.The atypical coproporphyrins II and IV were detected in all types of porphyria analysed and ranged from 0.2 to 9.0%; no significant differences were seen between acute and chronic hepatic porphyrias. The diagnostic importance of the isomer ratios of coproporphyrins I and III has been confirmed in our study, while the significance of the atypical Coproporphyrin isomers II and IV is still unclear at present.

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“…The isomer composition of isolated uroporphyrin was determined by decarboxylating it (17) and separating the resulting coproporphyrin isomers by thin-layer chromatography in lutidine-ammonia (4,18). The areas for isomers I and III were eluted with 0.7 M NH40H, diluted into 1 N HCl, and analyzed for coproporphyrin spectrophotometrically (13) or fluorometrically (19).…”

Section: Methodsmentioning

confidence: 99%

“…The chromophore from the bones and urine of fox squirrels was initially identified as uroporphyrin I on the basis of its absorption spectrum and melting point (2). In addition, the material behaves like uroporphyrin on chromatography in lutidine-ammonia (18). After esterification, it has the chromatographic properties of uroporphyrin methyl ester in dioxanekerosene (21).…”

Section: Methodsmentioning

confidence: 99%