Hemin chloride

Although arteflene 5 is not a 1,2,4-trioxane, its mechanism of action is believed to be very similar to trioxanes dne to the presence of the peroxide bond. Indeed, when radioactive C-arteflene was incnbated with P. falciparum, several alkylated parasitic proteins were identified . The O Neill gronp carried out the first iron(II) degradation studies of arteflene using iron(II) chloride in aqneons acetonitrile they isolated enone 63a (in tandem with radical 63b) and diol 64a (Scheme 19A). The degradation with heme (generated from hemin chloride by A-acetylcysteine) was observed to be slower, but afforded the same products although in different ratio. 

Carboxylic groups of the protoporphyrin IX ligand (Scheme 10) are phenomenal candidates for the targeted active-site modification of HRP and other heme-containing proteins. There is a clear parallel with the active site modification of GO (Section IV.A.2). The modification of hemin chloride by H2NCH2Fc in the presence of EDC and V-hydroxysuccinimide in DMF affording mono- and bis-amidated propionic acid residues is shown in Scheme 10 (144). The Fc Heme is actually a mixture of two diastereomers. -HRP has been prepared according to an acidic methyl ethyl ketone procedure of Teale (145)... 

There have been two additional experiments which verified this basic picture of the nuclear hyperfine interaction in hemins. Johnson (78) increased the spin-lattice relaxation time by performing the Mossbauer experiment under field and temperature conditions which provide a large value of H/T. At 1.6 °K and in an applied field of 30 kG, a magnetic hyperfine interaction corresponding to that expected for high spin Fe(III) and for the g-values is measured experimentally. Recently, Lang et al. have found that a portion of hemin chloride dissolved in tetrahydro-furan at 1 mM concentration displays a hyperfine interaction at 4 °K in zero applied magnetic field. Their conclusion is that a portion of the hemin is present in a monomeric form in this solvent, a situation which is not apparent to any extent in water, acetic acid, chloroform, or dimethyl sulfoxide (77) at any concentrations used. 

Thus, there appear to be analogies with the six-coordinate high-spin Fe(III) heme of the catalase with tyrosinate ligand [3], The green color of A1203 with applied hemin chloride is transformed to yellow after the catalase reaction, and the resonance Raman spectrum of the spent sample indicates at least partial intactness of the heme part. 

Figure 7.31 Resonance Raman spectra (a) free hemin chloride, (b) 1% biomimic (catalyst) and (c) biomimic after reaction with H202. Soret band at 406.7 nm laser power equals 80mW and resolution is 2cm 1.

Figure 4 Physical characterization of hemozoin. (a) The axial propionate linkages between heme units in FIZ are seen by FT-IR fingerprints of C = 0 and C-O stretching at 1664 and 1211 cm , respectively, (b) Characteristic 2 1 peaks are seen at T-. 21° and 24° 28 for (i) native and (ii) synthetic FIZ. Absent from these aggregates is the 23° 28 peak observed in the diffraction pattern of (iii) substrate hemin chloride, (c) Electron micrograph of FIZ in P. falciparum infected RBC where (i) is the host RBC, (ii) is the parasite, and (iii) is the DV. Image reproduced with kind permission of Springer Science and Business Media (23). (d) SEM image of uniform BFI crystals.

Figure 2. EPR spectra of a solution of hemin chloride in N,N-dimethylformamide...

Let us now examine some real EPR spectra taken from porphyrin samples. Hemin chloride dissolved in N,N-dimethylformamide gives the EPR spectra shown in Figure 2. The lower curve (absorption) extends from g = 6-2 and the upper curve (absorption derivative) excursion is very large near g = 6 but barely discemable at g = 2. As far as one can tell from such a spectrum, the system is axial that is, gp and gy are both equal to 6, while gz is equal to 2. One can easily convert the hemin to a low-spin compound by adding ligands which will replace chloride. One such hgand is mercaptoethanol. By adding mercaptoethanol to this... 

Figure 3. EPR spectra of the same sample of hemin chloride as was used previously (Figure 2) to which had been added mercaptoethanol...

Fig. 29. 406.7 nm-excited Raman spectra of hemin chloride (15 mAf) in aqueous base (bottom spectrum, a), and of a roughened silver electrode surface in contact with hemin chloride (0.15 mA/) in aqueous base and held at the indicated potentials versus SCE (b-e). Experimental conditions laser power, 30 mW, spectral slitwidth 5cm" , accumulation time 1 s, scan rate 1 cm /s (Sanchez and Spiro, Ref. 

Fig. 30. Cyclic voltammogram for a roughened silver electrode in aqueous (pH 10.5) hemin chloride (0.5 mA/) containing 0.1 M K.C1 as supporting electrolyte. Scan rate 100 mV/s (Sanchez and Spiro, Ref.

Fig. 8. A SNOOPI diagram (E. K. Davies, plotting routine, 1984, Chemical Crystallography Laboratory, 9 Parks Road, Oxford, England) of the hemin chloride of 202a (50% probability contours for all atoms hydrogen atoms have been omitted for clarity the dashed bonds are used to distinguish between the strap and the porphyrin skeleton)...

The inducing effect of chemicals that bring about a three- to four-fold increase in liver ALA-synthetase in 6 hours was found by Marver [109] to be nullified if simultaneously with the inducing chemical the large dose of 12 mg of hemin chloride (per 100 gm wt) was injected into the rat. 

Ferroheme is easily oxidized to ferriheme, containing iron(lll). Ferriheme chloride (old name hemin chloride) forms black crystals. Protoporphyrin is purple its color, the black color of hemin salts, and the red color of blood are related to the system of resonating double bonds in the porphyrin structure. 

Fig. 21 (a) 2D correlation NMR spectrum of hemin chloride obtained with dipolar INEPT... 

Hemin chloride (0.1247g, 0.193 mmol) was dissolved with stirring in 2,6-lutidine (3 mL, 0.030 Mol) over the course of IS minutes. This mixture is then diluted by addition of SO mL of MeOH and SO mL of DMSO and the mixture is allow l to stand without stirring. After nine days it was brought out of the inert atmosphere box and the DMSO/MeOH solvent was decanted off the solid phase. The solid was washed widi MeOH until the MeOH washes were colorless and clear. The solid product was dried in vacuo at room temperature to give 0.107g, (91 % yield) of a black fluffy powder... 

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