X‐Ray Photoelectron Spectroscopy of Mesoionic Compounds

Patsch, Manfred; Thieme, P.

doi:10.1002/anie.197105691

Cited by 19 publications

(6 citation statements)

References 7 publications

(1 reference statement)

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“…Unlike the 1.5 methionine residues found by amino acid analysis no methionine sulphur in the region between 162.5 to 163.0 eV was detectable in the XPS spectrum. Cysteine in the -SH form exhibits a XPS signal a t E (S 2p) = 162.9 eV whereas zwitterionic alkyl thiolates show much lower binding energies a t 161.1 eV [50]. Therefore, we have strong indications that most of the 36 cysteine residues are not in the protonated form.…”

Section: Evaluation Of X-ray Photoelectron Spectramentioning

confidence: 72%

Characterization of Cd, Zn‐Thionein (Metallothionein) Isolated from Rat and Chicken Liver

Weser

Rupp

Donay

et al. 1973

European Journal of Biochemistry

201

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The preparation of pure metallothionein from Cd-pretreated rats and chicken was performed using short-time treatment with chloroformlethano1 followed by ion-exchange and gel chromatography. The protein contained 7 g-atoms metal ions per 12000 g protein. The Zn to Cd ratio was 1 :2.4 f 0.1. The Cd, Zn-thionein remained homogeneous during Sephadex G-25, 6-50 and 6-75 gel filtration, during polyacrylamide disc-gel electrophoresis and in the analytical ultracentrifuge. The high content of cysteine residues (approx. one-third of the total residues) was consistent with the cysteine content of metallothionein isolated from human or equine tissues. The Cd, Znthionein was of considerable temperature stability. The physicochemical properties were examined by ultraviolet spectroscopy, circular dichroism (CD) measurements and X-ray photoelectron spectroscopy. The millimolar absorption coefficient of the native protein was a t 250nm ~2543 = 80.6 mM-1-cm-1. Virtually no aromatic amino acids were present. The E~~~ value of the apoprotein prepared by metal displacement using HC1 was E~~~ = 13.2 mM-1 * cm-l. When the ultraviolet spectrum of the apoprotein was recorded a t p H 6.6 a distinct peak was detectable at 255 nm (eZ5,, = 18.7 m M-1. om-l). The existence of inter-or intramolecular disulphide formation was confumed by CD measurements employing the polyethyleneglycol esters of di-tert-butyloxycarbonyl-L-cystine and tert-butyloxycarbonyl-L-cysteine as model aompounds for high-molecularweight and water-soluble cysteine compounds, respectively.From CD data it was concluded that Cd, Zn-thionein exists mainly as a random-coil peptide.Some indication of the binding of Cd and Zn in the native protein with eS-R moieties was obtained from ultraviolet data. Final proof of the exclusive coordination of these metal ions with cysteine sulphur was successful using both circular dichroism measurements and especially X-ray photoelectron spectroscopy. The last method proved most convenient for determining the binding energies of the core electrons of Cd (Cd 3d,,= = 411.0 eV and Cd 3d,ll = 404.4 eV), Zn (2 pal, =1021.0 eV) and S (2p = 161.7 eV). The corresponding binding energies for S in the cystine complexes with Zn2+ and Cd2+ were 163.0 eV and 162.8 eV, respectively.Sixteen years ago Margoshes andVallee were able to demonstrate the simultaneous presence of Cd, Zn and even Hg in a protein isolated from kidney cortex sulphur-containing amino acids, it was suggested the protein be named metallothionein. At the moment the discussion regarding the biochemical function of metallothionein is still going on. One important action would appear rather attractive : the decontamination of biological systems from harmful mercury and cadmium ions. This hypothesis has been supported by the observation of a rapid rise of metallothinein synthesis following the oral or intraperiotoneal administration of cadmium to rabbits [5,6], rats [7 to 91 and chicken [10,11].Although our knowledge of metauothionein is quite established, there is still considerable work ...

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Section: Evaluation Of X-ray Photoelectron Spectramentioning

confidence: 72%

Characterization of Cd, Zn‐Thionein (Metallothionein) Isolated from Rat and Chicken Liver

Weser

Rupp

Donay

et al. 1973

European Journal of Biochemistry

201

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“…X-ray photoelectron spectroscopy investigation shows that 4,5-disubstituted-1,3,4-thiadiazolium-2-thiolates, such as 4,5-diphenyl-1,3,4-thiadiazolium-2-thiolate and 4,5-di (p-chlorophenyl)-1,3,4-thiadiazolium-2-thiolate, et al are formally neutral mesoionic compounds [1] and Ollis and Ramsden have published an authoritative review on the chemistry of these mesoionic compounds [2]. Generally, the conditions of synthesis thiadiazole derivations are rigorous and the yields are low [3].…”

Section: Introductionmentioning

confidence: 98%

“…On the other hand, with the vast development of computational chemistry in the past decade, theoretical modeling of organic chemistry becomes much more mature than ever. Many important chemical and physical properties of the chemical system 1 New Materials & Function Coordination Chemistry Laboratory, Qingdao University of Science and Technology, Qingdao Shandong 266042, People's Republic of China. 2 Materials Chemistry Laboratory, Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China.…”

Section: Introductionmentioning

confidence: 99%

“…Generally, the conditions of synthesis thiadiazole derivations are rigorous and the yields are low [3]. However, in our laboratory, we synthesized 3-phenyl-5-phenylazo-3H- [1,3,4] thiadiazole-2-thione under very mild conditions, such as 40 • C, 1 atmospheric pressure and short reaction period, and determined its crystal structure. On the other hand, with the vast development of computational chemistry in the past decade, theoretical modeling of organic chemistry becomes much more mature than ever.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical and Experimental Study on 3-Phenyl-5-Phenylazo-3H-[1,3,4] Thiadiazole-2-Thione

et al. 2005

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3-Phenyl-5-phenylazo-3H-[1,3,4] thiadiazole-2-thione has been synthesized and characterized by X-ray diffraction and FTIR spectra. An extended MO calculation using density functional theory (DFT) at B3LYP/6-31g * level has been carried out. The results of the calculations were compared with experimental data and they are found to support each other. The thermodynamic properties of the title compound at different temperatures also have been calculated on the basis of vibration analyses.

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“…4-MethyI-2phenyl-1,3,4-thiodiazole-5-thione shows an N(ls) electron difference of 0.9 eV and an S(2p) electron difference of 2.1 eV. These measurements are indicative that mesionic 1,3,4-thiodiazole thiones exist predominantly in the betaine form (122). The ESCA spectra of DPPH and diphenylpicrylhydrazine have been recorded.…”

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confidence: 92%

Electron spectroscopy. II. X-ray photoexcitation

Hercules¹

1972

Anal. Chem.

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X‐Ray Photoelectron Spectroscopy of Mesoionic Compounds

Cited by 19 publications

References 7 publications

Characterization of Cd, Zn‐Thionein (Metallothionein) Isolated from Rat and Chicken Liver

Characterization of Cd, Zn‐Thionein (Metallothionein) Isolated from Rat and Chicken Liver

Theoretical and Experimental Study on 3-Phenyl-5-Phenylazo-3H-[1,3,4] Thiadiazole-2-Thione

Electron spectroscopy. II. X-ray photoexcitation

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