scholarly journals Cysteine-dependent inactivation of hepatic ornithine decarboxylase

1984 ◽  
Vol 217 (2) ◽  
pp. 573-580 ◽  
Author(s):  
Y Murakami ◽  
T Kameji ◽  
S Hayashi
Keyword(s):  
Absorption Spectrum ◽  
Ornithine Decarboxylase ◽  
Vitamin B6 ◽  
Liver Homogenate ◽  
Visible Region ◽  
The Other ◽  
Reactive Iron ◽  
Heat Stable ◽  
Dependent Inactivation ◽  
Liver Homogenates

When rat liver homogenate or its postmitochondrial supernatant was incubated with L-cysteine, but not D-cysteine, ornithine decarboxylase (ODC) lost more than half of its catalytic activity within 30 min and, at a slower rate, its immunoreactivity. The inactivation correlated with production of H2S during the incubation. These changes did not occur in liver homogenates from vitamin B6-deficient rats. A heat-stable inactivating factor was found in both dialysed cytosol and washed microsomes obtained from the postmitochondrial supernatant incubated with cysteine. The microsomal inactivating factor was solubilized into Tris/HCl buffer, pH 7.4, containing dithiothreitol. Its absorption spectrum in the visible region resembled that of Fe2+ X dithiothreitol in Tris/HCl buffer. On the other hand FeSO4 inactivated partially purified ODC in a similar manner to the present inactivating factor. During the incubation of postmitochondrial supernatant with cysteine, there was a marked increase in the contents of Fe2+ loosely bound to cytosolic and microsomal macromolecules. Furthermore, the content of such reactive iron in the inactivating factor preparations was enough to account for their inactivating activity. These data suggested that H2S produced from cysteine by some vitamin B6-dependent enzyme(s) converted cytosolic and microsomal iron into a reactive loosely bound form that inactivated ODC.

The absorption spectrum of nitrosyl chloride

1939 ◽  
Vol 172 (950) ◽  
pp. 432-444 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Fine Structure ◽  
Quantum Efficiency ◽  
Complete Solution ◽  
Visible Region ◽  
The Other ◽  
Nitrosyl Chloride ◽  
Sufficient Energy ◽  
Wide Range ◽  
Photochemical Decomposition

Although the photodecomposition of nitrosyl chloride has often been quoted as a typical photochemical reaction, there is considerable disagree ­ ment in the literature with regard to its exact mechanism. Early workers (Kiss 1923; Bowen and Sharpe 1925) found a quantum efficiency, γ , of 0.5 for the visual region, while Kistiakowsky (1930) found a value of 2. Quanta of wave-lengths shorter than 7600 A have sufficient energy to dissociate NOCl. Kistiakowsky, however, found fine structure in the spectrum as far down as 4100 A and suggested therefore that the reaction occurred as a result of a collision between a photochemically activated molecule and a normal molecule. On the other hand, Allmand (1931) pointed out that the fact that γ was not reduced (Kistiakowsky 1930) either by sevenfold dilution with nitrogen or reduction in pressure by a factor of nine, indicated a primary dissociation mechanism. He suggested the possibility of this occurring without the disappearance of rotational fine structure. Recently, Winn (1939) has found photochemical decomposition of NOCl to occur with a quantum efficiency of 2 down to extremely low pressures. The existence of rotational fine structure associated with primary dissociation still awaits clarification. The authors have therefore reinvestigated the absorption spectrum of nitrosyl chloride in the visible and ultraviolet regions, and have measured the extinction coefficients over a wide range. Manganini (1889) was the first to study this spectrum but made only qualitative measurements. Leermakers and Ramsperger (1932), incidental to another problem, measured the extinction coefficient of NOCl over a small part of the visible region, but made no mention of fine structure. The molecular structure of NOCl has been investigated recently by both infra-red and electron diffraction methods (Bailey and Cassie 1934; Ketelaar and Palmer 1937; Fox and Martin 1938). The molecule is apparently triangular, the only non-linear completely asymmetrical triatomic molecule reported in the literature.* The other nitrosyl halides are presumably similar. The characteristics of the vibrations of such a molecule still await complete solution.

scholarly journals The spectrum of thallium fluoride

1937 ◽  
Vol 160 (901) ◽  
pp. 242-253 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Kinetic Energy ◽  
The Other ◽  
Molecular Spectra ◽  
Absorption Tube ◽  
Saturated Vapour ◽  
Long Wave ◽  
Original Investigation ◽  
Wave Edge

This study of the thallium fluoride spectrum was undertaken as part of a detailed investigation into the molecular spectra of the series of heavy diatomic fluorides HgF, TlF, PbF and BiF. Whereas the spectra of PbF (Rochester 1936) and BiF (Howell 1936), of which analyses have already been published, contain no very unusual features the TlF spectrum is particularly rich in them, so that it has seemed desirable to extend the original investigation in order to include the other halides of thallium. The absorption spectrum of the fluoride has already been examined by Boizova and Butkow (1936), their findings being summarized below: 1— A continuum at 2200 A appears when the absorption tube is at a temperature of 155° C. Its long-wave edge moves towards the red with increase of temperature, being at 2700 for the unsaturated vapour and at 3400 for the saturated vapour when the temperature is 280° C. They attributed this continuum to the dissociation of Tl 2 F 2 . Tl 2 F 2 → 2TlF + kinetic energy.

Unusual spectral shifts in the prototropic reactions of 2,7-diaminofluorene

1987 ◽  
Vol 65 (9) ◽  
pp. 2013-2018 ◽  
Author(s):  
R. Manoharan ◽  
Sneh K. Dogra
Keyword(s):  
Absorption Spectrum ◽  
Aqueous Medium ◽  
Fluorescence Spectrum ◽  
Blue Shift ◽  
Proton Donor ◽  
Red Shift ◽  
The Other ◽  
Spectral Shifts ◽  
Other Hand

The red shift observed in the absorption spectrum of 2,7-diaminofluorene (DAF) in ether and acetonitrile is either due to the proton-donating capacity of the solute or due to its dispersive interactions with the solvent and a blue shift in methanol and water is due to the proton-accepting nature of DAF. DAF acts as a proton donor in S1 state in all solvents. The red shift in the fluorescence spectrum of the monocation of DAF relative to that of DAF is not because of the —NH2 group becoming more basic but because of the large solvent relaxating in aqueous medium. On the other hand, the monocation of DAF in cyclohexane follows the normal blue shift in the fluorescence spectrum. pKa values for the various prototropic reactions in S0 and S1 states are determined and discussed.

The electronic spectra of phenyl radicals

1965 ◽  
Vol 287 (1411) ◽  
pp. 457-470 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Electronic Absorption Spectrum ◽  
Electronic Absorption ◽  
Ground State ◽  
Electronic Spectra ◽  
Flash Photolysis ◽  
Visible Region ◽  
Electronic Configuration ◽  
Vibrational Structure ◽  
Fundamental Frequencies

An electronic absorption spectrum, attributed to phenyl, has been observed in the visible region with origin at 18 908 cm -1 after flash photolysis of benzene and halogenobenzenes. Similar spectra of fluoro, chloro and bromo phenyl are observed after flash photolysis of disubstituted benzenes. The vibrational structure of the phenyl spectrum has been analysed in terms of two fundamental frequencies at 571 and 896 cm -1 which correspond to the e 2 g and a 1 g frequencies of the B 2 u state of benzene. The ground state of phenyl has a π 6 n electronic configuration and the observed transition is interpreted as 2 A 1 → 2 B 1 resulting from a π → n excitation.

Cholesterol Metabolism and Vitamin B6. III. The Stimulation of Hepatic Cholesterogenesis in the Vitamin B6-Deficient Rat

1971 ◽  
Vol 49 (8) ◽  
pp. 933-935 ◽  
Author(s):  
C. M. Hinse ◽  
P. J. Lupien
Keyword(s):  
Vitamin B6 ◽  
Cholesterol Metabolism ◽  
Krebs Cycle ◽  
Pool Size ◽  
Liver Slices ◽  
Liver Homogenates ◽  
The Difference ◽  
Hepatic Cholesterogenesis ◽  
Stimulation Of

The rate of incorporation of labeled acetate into cholesterol by liver slices of pyridoxine-deficient rats was found to be three times that of control rats; with liver homogenates the difference between the two groups was even greater. Using the CO2 trapping technique, a 30% decrease in the hepatic acetate pool size was observed in pyridoxine-deficient rats and a 20% increase in pair-fed rats. Activity of the Krebs cycle was decreased by a third in the pair-fed rats.

scholarly journals SOLVOTHERMAL SYNTHESIS OF BI2WO6 AND ITS PHOTOCATALYTIC ACTIVITY UNDER VISIBLE LIGHT IRRADIATION

2018 ◽  
Vol 54 (4B) ◽  
pp. 42
Author(s):  
Trinh Duy Nguyen
Keyword(s):  
Absorption Spectrum ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Solvothermal Synthesis ◽  
Solvothermal Method ◽  
Visible Region ◽  
High Photocatalytic Activity ◽  
Light Irradiation ◽  
Different Temperatures

Flower-like Bi2WO6 were successfully synthesized using the solvothermal method at different temperatures and characterized by XRD, FE-SEM, and DRS. We also investigated the photocatalytic activity of Bi2WO6 for the decomposition of rhodamine B under visible light irradiation. From XRD and SEM results, the reaction temperature has significant effects on the morphologies of the samples. From DRS results, Bi2WO6 samples displayed the absorption spectrum up to the visible region and then they showed the high photocatalytic activity under visible light irradiation, as a comparison with TiO2-P25.

scholarly journals Features of free oxidation in liver homogenates of rats in combined action of copper and subtoxic level of stearate potassium and sodium

2016 ◽  
Author(s):  
O. V. Lototska
Keyword(s):  
Free Radical ◽  
Liver Homogenate ◽  
Sodium Stearate ◽  
Free Radical Oxidation ◽  
The Body ◽  
Antioxidant Systems ◽  
Radical Oxidation ◽  
Combined Action ◽  
Liver Homogenates ◽  
Free Oxidation

Toxic effects of heavy metals on animals and humans is aggravating the presence of surfactants. The aim of our research was to identify the peculiarities of free radical oxidation and antioxidant protection in the use of drinking water with subtoxic doses of potassium and sodium stearates in combination with copper on the body of warmblooded animals, such as the liver of experimental rats. Analysis of indicators allows asserting that in experimental rats liver homogenate observed activation of free radical oxidation, the intensity of which depended on the concentration of stearates in water. More pronounced changes were in animals that consumed water with potassium stearate.The action of potassium stearate observed inhibition of antioxidant systems while under the influence of sodium stearate – its activation. Changes in performance were more pronounced in combination stearates with copper.

scholarly journals Calmodulin is a major component of extruded trichocysts from Paramecium tetraurelia.

1981 ◽  
Vol 91 (3) ◽  
pp. 860-865 ◽  
Author(s):  
J J Rauh ◽  
D L Nelson
Keyword(s):  
Heat Treatment ◽  
Amino Acid ◽  
Affinity Chromatography ◽  
Amino Acid Composition ◽  
The Other ◽  
Paramecium Tetraurelia ◽  
Whole Cells ◽  
Molecular Weights ◽  
Heat Stable ◽  
Composition Characteristic

Extruded trichocysts are composed of a family of proteins with molecular weights between 15,000 and 20,000. We have used heat treatment and affinity chromatography on fluphenazine-Sepharose to purify calmodulinlike proteins from whole cells and from extruded trichocysts. The purified protein from trichocysts is indistinguishable from that of whole cells; it is heat-stable, activates brain phosphodiesterase in a Ca++-dependent fashion, changes mobility on SDS polyacrylamide gels in the presence of Ca++, contains 1 mol of trimethyllysine/17 kdaltons, and has the amino acid composition characteristic of calmodulins. Calmodulin is a major component of purified, extruded trichocysts, of which it represents between 1 and 10% by mass. The other proteins of the trichocyst also resemble calmodulin in several properties. Possible roles for calmodulin in the Ca++-activated extrusion of trichocysts is discussed.

scholarly journals THE ABSORPTION SPECTRUM OF VISUAL PURPLE

1938 ◽  
Vol 21 (4) ◽  
pp. 411-430 ◽  
Author(s):  
Aurin M. Chase ◽  
Charles Haig
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Light Transmission ◽  
Low Ph ◽  
The Other ◽  
Distilled Water ◽  
Color Purity ◽  
Chemical Combination ◽  
Ph Range ◽  
Sensitive Group

The absorption spectra of visual purple solutions extracted by various means were measured with a sensitive photoelectric spectrophotometer and compared with the classical visual purple absorption spectrum. Hardening the retinas in alum before extraction yielded visual purple solutions of much higher light transmission in the blue and violet, probably because of the removal of light-dispersing substances. Re-extraction indicated that visual purple is more soluble in the extractive than are the other colored retinal components. However, the concentration of the extractive did not affect the color purity of the extraction but did influence the keeping power. This suggests a chemical combination between the extractive and visual purple. The pH of the extractive affected the color purity of the resulting solution. Over the pH range from 5.5 to 10.0, the visual purple color purity was greatest at the low pH. Temperature during extraction was also effective, the color purity being greater the higher the temperature, up to 40°C. Drying and subsequent re-dissolving of visual purple solutions extracted with digitalin freed the solution of some protein impurities and increased its keeping power. Dialysis against distilled water seemed to precipitate visual purple from solution irreversibly. None of the treatments described improved the symmetry of the unbleached visual purple absorption spectrum sufficiently for it to resemble the classical absorption spectrum. Therefore it is very likely that the classical absorption spectrum is that of the light-sensitive group only and that the absorption spectra of our purest unbleached visual purple solutions represent the molecule as a whole.

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