Stabilization of Aqueous Hemin Solutions.

Maehly, A. C.; Åkeson, Åke; Bergson, Göran; Grönvall, A.; Zaar, B.; Diczfalusy, E.

doi:10.3891/acta.chem.scand.12-1259

Cited by 52 publications

(27 citation statements)

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“…Both haem and haematin are pictured as dimers, and though the degree of overlap of the rings is uncertain it must be insufficient to permit any iron-iron interactions except at high pH (Barron, 1937). Reaction (1) is the well-documented deterioration of aqueous haematin solutions on standing in light and air (Maehly & Akeson, 1958).…”

Section: Resultsmentioning

confidence: 99%

The formation of pyridine haemochromogen

Gallagher

Elliott

1965

Biochemical Journal

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1. Titration of haem with pyridine in alkaline media of low ionic strength yields a true pyridine haemochromogen, compound III, at very low concentrations of pyridine. 2. Graphical analysis of this titration gives the first spectrophotometric evidence for a dimeric haem. 3. Compound III is unstable and tends to aggregate to a second compound, compound II, whose formation is enhanced under those conditions favourable to hydrophobic bonding. 4. At higher concentrations ofpyridine, compound II is dispersed to yield the classical pyridine haemochromogen, compound I, whose spectral properties are essentially those ofpyridine haemochromogen in a non-aqueous medium.Since the elucidation of the nature of haemochromogen by Anson & Mirsky (1925) and the discovery by Keilin (1925) (v/v) RESULTSThe three compounds noted by Smith (1958Smith ( , 1959 in the titration of alkaline haem with pyridine are referred to below as compounds III, II and I in order of their appearance in the titration. Compound I is the final product of the titration, the classical pyridine haemochromogen. Table 1 lists the spectral properties of these compounds. The extinction coefficients given are the highest 187

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Section: Resultsmentioning

confidence: 99%

The formation of pyridine haemochromogen

Gallagher

Elliott

1965

Biochemical Journal

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“…[7] However, the information obtained for the dimerization is still fairly indirect, since hemin dimerization is primarily driven by -stacking of porphyrin rings, without intermolecular bonding by the Fe center, as illustrated in Figure 1b. [7][8][9] The characteristic L-edge features at the Fe sites [7] do of course depend on their interaction with the N moieties of the porphyrin ring, but the Fe center in hemin is also coordinated by a chloride ligand.…”

Section: Introductionmentioning

confidence: 99%

“…For example, iron protoporphyrin IX chloride (FePPIX-Cl, or hemin, Figure 1a) forms monomer species when dissolved in dimethyl sulfoxide (DMSO), while dimer structures are present in aqueous solution. [6][7][8][9] It is known that the electronic structure of hemin, especially the local electronic structure at the Fe center, which often serves as the major functional site, is altered due to dimerization. [7] Hemin oligomer species in various solvents have therefore been investigated previously by UV-Vis spectroscopy and X-ray absorption/emission spectroscopy (XAS/XES) at the Fe L-edge, [6][7][8][9] although the nature of the probed electronic transitions implied that the hemin intermolecular bonding interactions were probed rather indirectly.…”

Section: Introductionmentioning

confidence: 99%

Intermolecular bonding of hemin in solution and in solid state probed by N K-edge X-ray spectroscopies

Golnak

Xiao

Atak

et al. 2015

Phys. Chem. Chem. Phys.

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X-ray absorption/emission spectroscopy (XAS/XES) at the N K-edge of iron protoporphyrin IX chloride (FePPIX-Cl, or hemin) has been carried out for dissolved monomers in DMSO, dimers in water and for the solid state. This sequence of samples permits identification of characteristic spectral features associated with the hemin intermolecular bonding. These characteristic features are further analyzed and understood at the molecular orbital (MO) level based on the DFT calculations.2

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“…The precipitation and concomitant oxidation of these compounds lead to spectral degradation on a time scale of the same magnitude as that of these experiments (Shack and Clark, 1947;Maehly and Akeson, 1958;Brown et al, 1968). In some experiments using aqueous buffers, it was found that the degradation was sufficient to render any spectral measurements meaningless.…”

Section: Buffersmentioning

confidence: 66%

Porphyrin Adsorption by Clay Minerals

Kosiur

1977

Clays and clay miner.

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Abstract--A study was undertaken to investigate the adsorption of hemin, protoporphyrin and hematoporphyrin by kaolinite and a Ca-montmorillonite in aqueous solutions buffered at pH 4 and 9.Although experimental restrictions at pH 4 prevented the complete characterization of the adsorption isotherms, kaolinite did exhibit a saturation of exchange sites by the cationic porphyrins. Both kaolinite and montmorillonite displayed a similar saturation of sites by the porphyrins in their anionic forms at pH 9. The major differences in the adsorption isotherms are attributed to differences in the exchange capacities of the clays.Adsorption of the porphyrins at pH 9 was inhibited largely by phosphate treatment of the clays; this effect is interpreted as blockage of the anion exchange sites by irreversibly-bound phosphate.

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Stabilization of Aqueous Hemin Solutions.

Cited by 52 publications

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The formation of pyridine haemochromogen

The formation of pyridine haemochromogen

Intermolecular bonding of hemin in solution and in solid state probed by N K-edge X-ray spectroscopies

Porphyrin Adsorption by Clay Minerals

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