Many of the stability characteristics of horse ferrihemoglobin (Hb+) in acid solutions, such as pH dependence and susceptibility to stabilization by iron ligands, are shared by human ferrihemoglobin, but striking differences between the two proteins exist. The most noticeable is the much greater rate of denaturation of the human protein at all pH values. Other differences include a shift to hig...

Hemin chlorides exhibit two absorption maxima in the Soret region, one at about 360-380 nm (S' band) and the other between 400 and 430 nm (S band). We present here a simple and fast spectrophotometric assay to determine concentration of hemin between 1.15 and 9.20 microM employing the Soret region (S' band) as a reference. In this method the hemin is quantitatively extracted from biological mat...

Irradiation of a soluble extract from broken cells of Dictyostelium discoideum causes the photoreduction of a b-type cytochrome. The cytochrome b can be separated from cytochrome c, which is also present in the extract, by column chromatography on Brushite, but the cytochrome b is no longer sensitive to light after separation on the column. Low temperature spectroscopy shows that reduced form o...

We describe a unique UV-visible absorption spectral property of 5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin (THPP) in the presence of organophosphorus (OP) pesticides. Upon titrating each 16 among total 40 different OP pesticides, the Soret band was significantly red-shifted, and a very intense Q band appeared. They were attributed to the diprotonation of THPP. A suitable solvent for this rea...

SINCE Soret [1883] described an ultraviolet absorption band in three of the haemoglobin series, numerous investigations have been carried out on the ultraviolet absorption spectrum of the blood pigment and its immediate derivatives. The haemoglobin compounds were investigated by Gamgee [1895] who pointed out that there was a specific ultraviolet band common to oxyhaemoglobin, reduced haemoglobi...

A simulation study demonstrates how coherent control, combined with adaptive polarization pulse shaping and a genetic algorithm, may be used to simplify femtosecond coherent nonlinear optical signals of excitons. Cross peaks are amplified and resolved, and diagonal peaks are suppressed in the heterodyne-detected two-pulse echo signal from the Soret band of a porphyrin dimer coupled to a Brownia...

In previous papers we have described methods for accurately measuring the spectra that represent the differences between the oxidized and the reduced forms of the cytochrome components of the turbid heart muscle particles that contain the intact succinic oxidase system (1, 2). In order to extend the pioneer observations of Keilin and Hartree on the carbon monoxide compound of cytochrome a3 (3) ...

A comparative study of the resonance Raman spectra of a number of hemoproteins with excitation in the Soret region reveals features that characterize the valence and spin state of the iron. (a) The frequency of the strongest band in the spectra for reduced (ferrous) hemoproteins always occurs between 1356 and 1361 cm-l, whereas for oxidized (ferric) proteins it occurs between 1370 and 1378 cm-l...

i The Soret circular dichroism (CD) spectrum of carbonmonoxy myoglobin dtifers strikingly for the two heme isomers: Aqzl =+90 M-’cm-’ for isomer A, AQ21 = -7 M-’cm-’ for isomer B (Aojula et al., BiochemJ. 250, 853(1988)). This observation implies significant differences in the protein conformation andlor distortions of the heme from planarity between the two isomers. Molecular dynamics simulati...