Hemoglobin In Aqueous Solution Research Articles

Hydrophilic molecularly imprinted microspheres functionalized with amino and carboxyl groups for highly selective recognition of human hemoglobin in aqueous solution

HMIMs functionalized with amino and carboxyl groups were synthesized for HHb. The HMIMs exhibit selective recognition properties toward the target protein. QCM results demonstrate the HMIMs coated electrode shows a more sensitive response to HHb than the NIMs coated one.

Fluorescence Enhancement of Imidazolium Ionic Liquid by Its Confinement on PVC for In Situ Selective Quantification of Hemoglobin

A hydrophilic ionic liquid (methylimidazolium chloride, NmimCl)-polyvinyl chloride ionomer (NmimCl-PVC) was prepared by immobilizing and confining N-methylimidazole onto PVC chains. The NmimCl-PVC ionomer exhibits a 4-fold enhancement on the fluorescence intensity with respect to that of NmimCl, attributing to the confinement of ionic liquid by the PVC chain. The fluorescence is excitation-dependent with a maximum at λem 430 nm when excited at 325 nm. In addition, the fluorescence intensity of NmimCl-PVC ionomer increases remarkably with the loading ratio of N-methylimidazole in the range of 4.3-15.1%. The fluorescence quantum yield and lifetime were derived to be 0.112/7.1 ns for the NmimCl-PVC ionomer and 0.063/8.8 ns for NmimCl. Furthermore, hemoglobin is selectively adsorbed by NmimCl-PVC and causes significant fluorescence quenching of the ionomer via dynamic quenching and energy transfer between NmimCl-PVC and hemoglobin. A solid surface fluorimetric procedure was developed for surface adsorption and preconcentration of hemoglobin followed by in situ detection. A linear dynamic range of 0.3-26.2 μg mg(-1) is achieved with a detection limit of 0.1 μg mg(-1). Regarding hemoglobin in aqueous solution, the linear range 5-300 μg mL(-1) is achieved along with a detection limit of 2 μg mL(-1).

Interaction between the Natural Lipopeptide [Glu1, Asp5] Surfactin-C15 and Hemoglobin in Aqueous Solution

The interaction between natural lipopeptide [Glu(1), Asp(5)] surfactin-C15 (surfactin) and hemoglobin (Hb) has been studied. Surface tension measurements show that the critical micelle concentration (cmc) of surfactin increases from 1.54 x 10(-5) to 3.86 x 10(-5) mol/L with Hb. The UV spectra display that the effect of surfactin on Hb exhibits strong concentration-dependent fashion and the aquometHb convert to hemichrome at high surfactin concentration. Small-angle neutron scattering (SANS) and freeze-fracture transmission electron microscopy (FF-TEM) measurements show that surfactin result in the formation of a fractal structure representing a "necklace model" of micelle-like clusters randomly distributed along the protein polypeptide chain at high surfactin concentration. Far-UV circular dichroism (CD) results confirmed that surfactin can disrupt the helical structure of protein at high concentrations, although the enhanced native-like behavior of protein by low concentration of surfactin was observed. The microenvironment change around Phe amino residues and disulfide bonds of Hb was obtained from near-UV CD spectra.

High magnetic field effects on human deoxygenated hemoglobin light absorption

The effect of high static magnetic field on human deoxyhemoglobin spectrophotometric characteristics is studied. Five samples of partially deoxygenated hemoglobin in aqueous solution were tested. Magnetic field was applied in steps of 2 T (tesla), from 0 to 18 T. Spectral analysis showed a higher light absorption at wavelengths of 546 nm and at 581 nm. The applied magnetic field did not alter the wavelengths at which the absorption peaks occurred. On the other hand, the light absorption was found to increase with the applied magnetic field strength up to 14 T.

CO cage recombination in hemoglobin: Picosecond photolysis and nanosecond observation

Carboxy hemoglobin in aqueous solution was photodissociated by laser pulses of 30 ps at 532 nm. Kinetic studies show that only upon complete photodissociation can the pure CO geminate binding process be revealed. The protein region of the iron cage, where the geminate ligand diffuses before reaching the heme, is smaller than a single subunit and larger than the heme pocket.

Thermodynamic studies on hemoglobin solutions

AbstractThe heat of solution and the osmotic pressure of bovin hemoglobin in aqueous solution have been measured at 298 K using a twin microcalorimeter and an osmometer. The heat of association, ΔH, from calorimetric measurement and the association equilibrium constant, K, from osmometric measurement have been estimated, respectively. Also the thermodynamic quantities of the hemoglobin molecule which associates from 2αβ to the original α2β2 form are calculated. In all systems of the hemoglobin solutions, the value of dissociation equilibrium constant, K', calculated as the reciprocal of K, and that of ΔH seem to be of comparable order to those determined by the other investigators.

Chlorpromazine as a substitute for ortho-dianisidine and ortho-tolidine in the determination of chlorine, hemoglobin, and peroxidase activity

1. Chlorpromazine is readily oxidized to its red semiquinone free radical in acid solution, and this was made the basis for the following methods. EDTA was added in each case to minimize interference by Fe and Mn. 2. Available chlorine in water was determined with chlorpromazine as chromogen, but this did not distinguish between free chlorine and chloramine. Then sensitivity of the method was about one-fifth of that of an o -tolidine method. 3. Chlorpromazine was an excellent chromogen for estimation of micro-quantities of hemoglobin in aqueous solution, thus confirming the results of Lee and Ling (1969) . The method was more precise and more sensitive than an o -tolidine method. 4. Chlorpromazine could be substituted for o -dianisidine in an assay of peroxidase activity, but it was somewhat less sensitive than the latter method. 5. The chlorpromazine-peroxidase system was not satisfactory for the determination of low concentrations of hydrogen peroxide.

X‐Ray and Neutron Small‐Angle Scattering from Hemoglobin in Aqueous Solution and in Crystal

The small‐angle scattering function of hemoglobin for X‐rays and neutrons has been calculated from the atomic coordinates of hemoglobin, established by X‐ray diffraction analysis. These theoretical scattering functions were compared with the experimental scattering data on aqueous hemoglobin solutions reported previously. The good agreement of the two sets of data in and beyond the region of the Guinier approximation gives confidence to the statement that the three‐dimensional structures of hemoglobin in single crystal and in aqueous solution are the same.

Quantitative measurement of gastrointestinal blood loss: I. The use of radioactive Cr 51 in patients with gastrointestinal hemorrhage

1. 1. A method for quantitating the amount of blood lost in the feces by means of erythrocytes labeled with radioactive sodium chromate is described. The maximum amount of blood lost by normal subjects is 1.2 ± 0.5 ml., with a range of 0.3 to 2.0 ml. of whole blood per day. 2. 2. The sensitivity of the qualitative benzidine dihydrochloride test to hemoglobin in aqueous solution has been compared with the sensitivity to hemoglobin in homogenized stools. It was found that the sensitivity of the test was approximately 100 times greater for hemoglobin in aqueous solution than for hemoglobin present in the stools. 3. 3. The use of the Cr 51 technic for quantitating blood loss from the gastrointestinal tract, combined with intestinal intubation for localizing the level of bleeding, has been tested in nine cases in which there was difficulty either in establishing that the anemia was due to blood loss or in localizing the level of bleeding by x-ray studies. In eight of the nine cases these technics were of aid in arriving at the correct diagnosis. In one case the interpretation of the Cr 51 and intubation data was not substantiated by the findings at operation.

The reaction between oxygen and hemoglobin

There are at present four different views as to the nature of the absorption of oxygen by blood.The first and oldest view is expressed by the reation, 1 mol. hemoglobin + 1 mol. oxygen 1 mol. oxyhemoglobin. According to the law of mass action one would havein which a represents the concentration of hemoglobin in solution, b the oxygen concentration, c the concentration of oxyhemoglobin, and k a constant.The second view is that of Bohr. Bohr assumed that hemoglobin in aqueous solution is hydrolytically split into globin + Fe-component, and that the Fe-component combines reversibly with oxygen. Bohr's formulation of this hypothesis leads to an equation of the fourth degree. Without going into details it will suffice to call attention to the main points of Bohr's work as far as we are concerned here. They are, in addition to the assumed hydrolysis of hemoglobin in aqueous solution, first, the inapplicability of formula (1) to his results and secondly, the variation of the ratio oxygen absorbed/total hemoglob...