共查询到20条相似文献,搜索用时 437 毫秒
1.
Jahan Bakhsh Raoof Reza Ojani Maryam Ramine 《Journal of Solid State Electrochemistry》2009,13(9):1311-1319
A p-duroquinone (tetramethyl-p-benzoquinone) modified carbon paste electrode (DMCPE) was employed to study the electrocatalytic reduction of nitrite in
aqueous solutions using cyclic voltammetry (CV), double potential-step chronoamperometry, and differential pulse voltammetry
(DPV). It has found that under an optimum condition (pH 1.00), the reduction of nitrite at the surface of DMCPE occurs at
a potential of about 660 mV less negative than that of an unmodified carbon paste electrode (CPE). The catalytic rate constant,
k′h, based on Andrieux and Saveant theoretical model was calculated as for scan rate 10 mV s-1. Also, the apparent diffusion coefficient, D
app, was found as 2.5 × 10–10 and 3.61 × 10–5 cm2 s-1
for p-duroquinone in carbon paste matrix and nitrite in aqueous buffered solution, respectively. The values for αnα were estimated to be −0.65 and −0.19 for the reduction of nitrite at the surface of DMCPE and CPE, respectively. The electrocatalytic
reduction peak currents showed a linear dependence on the nitrite concentration, and a linear analytical curve was obtained
in the ranges of 5.0 × 10–5 M to 8.0 × 10–3 M and 6.0 × 10–6 M to 8.0 × 10–4 M of nitrite concentration with CV and DPV methods, respectively. The detection limits (2σ) were determined as 2.5 × 10–5 M and 4.3 × 10–6 M by CV and DPV methods. This method was also applied as a simple, selective and precise method for determination of nitrite
in real samples (the weak liquor from the wood and paper factory of Mazandaran province in Iran) by using a standard addition
method. 相似文献
2.
Ab initio UMP2 and UQCISD(T) calculations, with 6-311G** basis sets, were performed for the titled reactions. The results show that
the reactions have two product channels: NH2+ HNCO?NH3+NCO (1) and NH2+HNCO?N2H3+CO (2), where reaction (1) is a hydrogen abstraction reaction via an H-bonded complex (HBC), lowering the energy by 32.48
kJ/mol relative to reactants. The calculated QCISD(T)//MP2(full) energy barrier is 29.04 kJ/mol, which is in excellent accordance
with the experimental value of 29.09 kJ/mol. In the range of reaction temperature 2300–2700 K, transition theory rate constant
for reaction (1) is 1.68×1011–3.29×1011 mL·mol-1·s-1, which is close to the experimental one of 5.0×1011mL·mol-1·s-1or less. However, reaction (2) is a stepwise reaction proceeding via two orientation modes,cis andtrans, and the energy barriers for the rate-control step at our best calculations are 92.79 kJ/mol (forcis-mode) and 147.43 kJ/mol (fortrans-mode), respectively, which is much higher than reaction (1). So reaction (1) is the main channel for the titled reaction. 相似文献
3.
Shangfen Gao Guangqun Tan Hongyan Yuan Dan Xiao Martin M. F. Choi 《Mikrochimica acta》2006,153(3-4):159-162
A simple and green analytical procedure based on chlorophyll a is presented for the determination of Hg2+ ion. Chlorophyll a was extracted and purified from the leaves of pea and is employed as a reagent for analysis of Hg2+ ion. It displays remarkable fluorescence emission at 674 nm when excited at 412 nm. The emission intensity decreased significantly
on exposure to various concentrations of Hg2+ ion. This forms the basis for the determination of Hg2+ ion. The proposed method was evaluated for sensitivity and selectivity. The linear concentration range was found to be 2.0–10 μM
with r2 = 0.997 and the limit of detection for Hg2+ ion was 1.3 μM. Ions including Pb2+, Cd2+, Ag+, Zn2+, Co2+, Ni2+, Cu2+, Mg2+, Mn2+, Ru3+, Er3+, K+, Na+, NH4+, Cl−, NO3−, CH3COO− and SO42− did not interfere with the measurement of Hg2+ ion even at 500-fold excess. Since chlorophyll a is widely available in the leaves of most plants, and the extraction and purification process is simple, this technique can
provide an alternative, sensitive and economical way to determine Hg2+ ion. 相似文献
4.
Eduardo Marafon Lauro T. Kubota Yoshitaka Gushikem 《Journal of Solid State Electrochemistry》2009,13(3):377-383
SiO2/ZrO2/C carbon ceramic material with composition (in wt%) SiO2 = 50, ZrO2 = 20, and C = 30 was prepared by the sol–gel-processing method. A high-resolution transmission electron microscopy image
showed that ZrO2 and the graphite particles are well dispersed inside the matrix. The electrical conductivity obtained for the pressed disks
of the material was 18 S cm−1, indicating that C particles are also well interconnected inside the solid. An electrode modified with flavin adenine dinucleotide
(FAD) prepared by immersing the solid SiO2/ZrO2/C, molded as a pressed disk, inside a FAD solution (1.0 × 10−3 mol L−1) was used to investigate the electrocatalytic reduction of bromate and iodate. The reduction of both ions occurred at a peak
potential of −0.41 V vs. the saturated calomel reference electrode. The linear response range (lrr) and detection limit (dl)
were: BrO3
−, lrr = 4.98 × 10−5–1.23 × 10−3 mol L−1 and dl = 2.33 μmol L−1; IO3
−, lrr = 4.98 × 10−5 up to 2.42 × 10−3 and dl = 1.46 μmol L−1 for iodate. 相似文献
5.
Stefan E. Boiadjiev David A. Lightner 《Monatshefte für Chemie / Chemical Monthly》2002,1(1):1469-1480
Malonic ester derivatives of ethyl and methyl 3,5-dimethyl-4-(1′-iodoneopentyl)-1H-pyrrole-2-carboxylate exhibit restricted rotation about the pyrrole C(4)–C(1′) bond due to the bulky 1′-tert-butyl and malonic ester groups and the ortho effect at C(4) of the sterically crowded 3,5-dimethylpyrrole. The malonates belong to a rare class of atropisomers with restricted rotation about an sp3–sp2 C–C bond, and they undergo diastereomeric separation by TLC and crystallization: the diastereomers are stable in solution at room temperature. A crystal of one of the diastereomers, suitable for X-ray crystallography, gave the relative configuration of the chiral axis and stereogenic center at C(1′). Dynamic NMR studies of the purified diastereomers provide kinetic and thermodynamic parameters associated with the atropisomerism: ΔG ‡ = 132–134 kJ/mol (∼32 kcal/mol) at 383 K in C2D2Cl4 solvent. 相似文献
6.
Relative enthalpies for low-and high-temperature modifications of Na3FeF6 and for the Na3FeF6 melt have been measured by drop calorimetry in the temperature range 723–1318 K. Enthalpy of modification transition at 920
K, δtrans
H(Na3FeF6, 920 K) = (19 ± 3) kJ mol−1 and enthalpy of fusion at the temperature of fusion 1255 K, δfusH(Na3FeF6, 1255 K) = (89 ± 3) kJ mol−1 have been determined from the experimental data. Following heat capacities were obtained for the crystalline phases and for
the melt, respectively: C
p(Na3FeF6, cr, α) = (294 ± 14) J (mol K)−1, for 723 = T/K ≤ 920, C
p(Na3FeF6, cr, β) = (300 ± 11) J (mol K)−1 for 920 ≤ T/K = 1233 and C
p(Na3FeF6, melt) = (275 ± 22) J (mol K)−1 for 1258 ≤ T/K ≤ 1318. The obtained enthalpies indicate that melting of Na3FeF6 proceeds through a continuous series of temperature dependent equilibrium states, likely associated with the production of
a solid solution.
相似文献
7.
Godin JP Faure M Breuille D Hopfgartner G Fay LB 《Analytical and bioanalytical chemistry》2007,388(4):909-918
We describe a new method of assessing, in a single run, 13C isotopic enrichment of both Val and Thr by gas chromatography–combustion–isotope-ratio mass spectrometry (GC–C–IRMS). This
method characterised by a rapid one-step derivatisation procedure performed at room temperature to form the N(O,S)-ethoxycarbonyl ethyl ester derivatives, and a polar column for GC. The suitability of this method for Val and Thr in in-vivo
samples (mucosal hydrolysate) was demonstrated by studying protein metabolism with two tracers (13C-valine or 13C-threonine). The intra-day and inter-day repeatability were both assessed either with standards or with in-vivo samples at
natural abundance and at low 13C isotopic enrichment. For inter-day repeatability CVs were between 0.8 and 1.5% at natural abundance and lower than 5.5%
at 0.112 and 0.190 atom% enrichment for Val and Thr, respectively. Overall isotopic precision was studied for eleven standard
amino acid derivatives (those of Val, Ala, Leu, Iso, Gly, Pro, Asp, Thr, Ser, Met, and Phe) and was assessed at 0.32‰. The
13C isotopic measurement was then extended to the other amino acids (Ala, Val, Leu, Iso, Gly, Pro, Thr, and Phe) at natural
abundance for in-vivo samples. The isotopic precision was better than 0.002 atom% per amino acid (for n = 4 rats). This analytical method was finally applied to an animal study to measure Thr utilization in protein synthesis. 相似文献
8.
Stefan E. Boiadjiev David A. Lightner 《Monatshefte für Chemie / Chemical Monthly》2002,133(11):1469-1480
Summary. Malonic ester derivatives of ethyl and methyl 3,5-dimethyl-4-(1′-iodoneopentyl)-1H-pyrrole-2-carboxylate exhibit restricted rotation about the pyrrole C(4)–C(1′) bond due to the bulky 1′-tert-butyl and malonic ester groups and the ortho effect at C(4) of the sterically crowded 3,5-dimethylpyrrole. The malonates belong to a rare class of atropisomers with restricted
rotation about an sp3–sp2 C–C bond, and they undergo diastereomeric separation by TLC and crystallization: the diastereomers are stable in solution
at room temperature. A crystal of one of the diastereomers, suitable for X-ray crystallography, gave the relative configuration
of the chiral axis and stereogenic center at C(1′). Dynamic NMR studies of the purified diastereomers provide kinetic and
thermodynamic parameters associated with the atropisomerism: ΔG
‡ = 132–134 kJ/mol (∼32 kcal/mol) at 383 K in C2D2Cl4 solvent.
Corresponding author. E-mail: lightner@scs.unr.edu
Received July 1, 2002; accepted July 8, 2002 相似文献
9.
The electrochemical behaviors of metol on an ionic liquid N-butylpyridinium hexafluorophosphate modified carbon paste electrode (IL-CPE) were studied in this paper. The results indicated
that a pair of well-defined quasi-reversible redox peaks of metol appeared with the decrease of overpotential and the increase
of redox peak current, which was the characteristics of electrocatalytic oxidation. The electrocatalytic mechanism was discussed
and the electrochemical parameters were calculated with results of the charge-transfer coefficient (α) as 0.45, the electrode reaction rate constant (k
s) as 4.02 × 10−3 s−1, and the diffusion coefficient (D) as 6.35 × 10−5 cm2/s. Under the optimal conditions, the anodic peak current was linear with the metol concentration in the range of 5.0 × 10−6 ∼ 1.0 × 10−3 mol/L (n = 11, γ = 0.994) and the detection limit was estimated as 2.33 × 10−6 mol/L (3σ). The proposed method was successfully applied to determination of metol content in synthetic samples and photographic solutions. 相似文献
10.
The geometrical parameters, normal vibration frequencies, and thermochemical characteristics of the Na2Cl+, NaCl
2
−
, Na3Cl
2
+
, and Na2Cl
3
−
ions in saturated vapors over sodium chloride were calculated by the ab initio methods including electron correlation. According to calculations, the Na2Cl+ and NaCl
2
−
triatomic ions have a linear equilibrium D
∞h
configuration. The pentaatomic ions can exist in the form of the D
∞h
linear isomer, C
2v
planar cyclic isomer, or D
3h
bipyramidal isomer. At ∼1000 K the Na3Cl
2
+
and Na2Cl
3
−
ions exist predominantly in the form of the linear isomers. The energies and enthalpies of the ion-molecule reactions involving
the above ions were calculated. The formation enthalpy of the ions Δf
H
0(0 K) was determined: 230 ± 2 kJ/mol (Na2Cl+), −96 ± 4 kJ/mol (Na2Cl
3
−
), −616 ± 2 kJ/mol (NaCl
2
−
), and −935 ± 4 kJ/mol (Na2Cl
3
−
).
Original Russian Text Copyright ? 2007 by T. P. Pogrebnaya, A. M. Pogrebnoi, and L. S. Kudin
__________
Translated from Zhurnal Strukturnoi Khimii, Vol. 48, No. 6, pp. 1053–1061, November–December, 2007. 相似文献
11.
Ab initio calculations of both ClCH2OCH3 and ClCH2CH3 molecules and various ClCH2OCH3 structures with fixed angles of rotation of the methoxy group about the C−O bond were performed by the restricted Hartree-Fock
method in the valence-split 6–31 G* basis set with full optimization of the geometry. The populations of the valent p-orbitals of the chlorine atoms in these
molecules have been analyzed. The35Cl NQR frequencies and the asymmetry parameters of the electric field gradient (EFG) at the35Cl nuclei have been calculated. Good agreement with experimental NQR frequencies was obtained for the calculations where only
the populations of the less diffuse 3p-components of these orbitals were used. The35Cl NQR frequency in ClCH2OCH3 is lower than that in ClCH2CH3 due to the higher population of the less diffuse component of the pσ-orbital of the Cl atom in the former molecule.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 431–434, March, 1997. 相似文献
12.
Molar excess volumes, V
ijk
E, and speeds of sound, U
ijk
, of o-toluidine (i) + benzene (j) + cyclohexane or n-hexane or n-heptane (k) ternary mixtures have been measured as a function of composition at 308.15 K. The observed speed of sound data have been
utilized to determine the excess isentropic compressibilities, (K
S
E)
ijk
, of the ternary (i+j+k) mixtures. The Moelywn-Huggins concept (Huggins in Polymer 12: 389–399, 1971) of connectivity between the surfaces of the binary mixture constituents has been extended to ternary mixtures (using the
concept of a connectivity parameter of third degree of molecules, 3
ξ, which in turn depends on its topology) to obtain an expression that describes well the measured V
ijk
E and (K
S
E)
ijk
data. The observed data have also been analyzed in terms of Flory’s theory. 相似文献
13.
Summary. Conformational analysis and frequency calculation were achieved for 1-phenyl-1,2-propandione 1-oxime and its four tautomers:
1-nitroso-1-phenyl-1-propen-2-ol, 1-nitroso-1-phenyl-2-propanone, 2-hydroxy-1-phenyl-propenone oxime, and 3-nitroso-3-phenyl-propen-2-ol.
Calculations were carried out at the Hartree–Fock (HF), Density Functional Theory (B3LYP), and the second-order M?ller–Plesset perturbation (MP2) levels of theory using 6-31G* and 6-311G** basis sets. Five conformers with no imaginary vibrational frequency were obtained by free rotations around three single bonds
of 1-phenyl-1,2-propandione-1-oxime: Ph–C(NOH)C(O)CH3, PhC(NOH)–C(O)CH3, and PhC(N–OH)C(O)CH3. Similarly, eight structures with no imaginary vibrational frequency were encountered upon rotations around three single
bonds of 1-nitroso-1-phenyl-1-propen-2-ol: Ph–C(NO)C(OH)CH3, PhC(N–O)C(OH)CH3, and PhC(NO)C(–OH)CH3. In the same manner, six minima were found through rotations around three single bonds of 1-nitroso-1-phenyl-2-propanone:
Ph–CH(NO)C(O)CH3, PhCH(–NO)C(O)CH3, and PhCH(NO)–C(O)CH3. Also, two minima were found through rotations around four single bonds of 2-hydroxy-1-phenyl-propenone oxime: Ph–C(NOH)C(OH)CH2, PhC(N–OH)C(OH)CH2, PhC(NOH)–C(OH)CH2, and Ph-C(NOH)C(–OH)CH2. Finally, two minima were found through rotations around four single bonds of 3-nitroso-3-phenyl-propen-2-ol: Ph–CH(NO)C(OH)CH2, PhCH(–NO)C(OH)CH2, PhCH(NO)–C(OH)CH2, and PhCH(NO)C(–OH)CH2. Interconversions within the above sets of conformers were probed through scanning (one and/or two dimensional), and/or QST3
techniques. The order of the stability of global minima encountered was: 1,2-propandione-1-oxime > 1-nitroso-1-phenyl-2-propanone
> 1-nitroso-1-phenyl-1-propen-2-ol > 2-hydroxy-1-phenyl-propenone oxime > 3-nitroso-3-phenyl-propen-2-ol. Hydrogen bonding
appears significant in tautomers of 1-nitroso-1-phenyl-1-propen-2-ol and 2-hydroxy-1-phenyl-propenone oxime. The CIS simulated
λmax for the first excited singlet state (S1) of 1-phenyl-1,2-propandione 1-oxime is 300.4 nm, which was comparable to its experimental λmax of 312.0 nm. The calculated IR spectra of 1-phenyl-1,2-propandione 1-oxime and its tautomers were compared to the experimental
spectra. 相似文献
14.
A. V. Afonin D. E. Perez M. C. Ruiz de Azua R. H. Contreras P. Lazzeretti 《Russian Chemical Bulletin》1997,46(2):292-296
Participation of the proton in a specific intramolecular C−H...X (X=N, 0) interaction leads to an increase in its geminal1H−1H and1H−31P spin-spin coupling constants (SSCC). According toab initio calculations carried out in the 6–31G** basis set, the observed effect is mainly due to the change in the diamagnetic spin-orbital contribution to SSCC.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 306–309, February, 1997. 相似文献
15.
S. P. Chen X. X. Meng Q. Shuai B. J. Jiao S. L. Gao Q. Z. Shi 《Journal of Thermal Analysis and Calorimetry》2006,86(3):767-774
A
solid complex Eu(C5H8NS2)3(C12H8N2) has been obtained from reaction of
hydrous europium chloride with ammonium pyrrolidinedithiocarbamate (APDC)
and 1,10-phenanthroline (o-phen⋅H2O)
in absolute ethanol. IR spectrum of the complex indicated that Eu3+
in the complex coordinated with sulfur atoms from the APDC and nitrogen atoms
from the o-phen. TG-DTG investigation provided
the evidence that the title complex was decomposed into EuS.
The
enthalpy change of the reaction of formation of the complex in ethanol, Δr
H
m
θ(l), as –22.214±0.081 kJ mol–1,
and the molar heat capacity of the complex, c
m,
as 61.676±0.651 J mol–1 K–1,
at 298.15 K were determined by an RD-496 III type microcalorimeter. The enthalpy
change of the reaction of formation of the complex in solid, Δr
H
m
θ(s), was calculated as 54.527±0.314 kJ mol–1
through a thermochemistry cycle. Based on the thermodynamics and kinetics
on the reaction of formation of the complex in ethanol at different temperatures,
fundamental parameters, including the activation enthalpy (ΔH
≠
θ),
the activation entropy (ΔS
≠
θ),
the activation free energy (ΔG
≠
θ),
the apparent reaction rate constant (k),
the apparent activation energy (E), the
pre-exponential constant (A) and the reaction
order (n), were obtained. The constant-volume
combustion energy of the complex, Δc
U,
was determined as –16937.88±9.79 kJ mol–1
by an RBC-II type rotating-bomb calorimeter at 298.15 K. Its standard enthalpy
of combustion, Δc
H
m
θ,
and standard enthalpy of formation, Δf
H
m
θ,
were calculated to be –16953.37±9.79 and –1708.23±10.69
kJ mol–1, respectively. 相似文献
16.
N. M. Klimenko E. A. Rykova M. L. McKee I. N. Senchenya 《Russian Chemical Bulletin》1999,48(3):417-427
Ab initio MP2/6-31G*//HF/6-31G*+ZPE(HF/6-31G*) calculations of the potential energy surface in the vicinity of stationary points and the pathways of intramolecular rearrangements
between low-lying structures of the OBe3F3
+ cation detected in the mass spectra of μ4-Be4O(CF3COO)6 were carried out. Ten stable isomers with di- and tricoordinate oxygen atoms were localized. The relative energies of six
structures lie in the range 0–8 kcal mol−1 and those of the remaining four structures lie in the range 20–40 kcal mol−1. Two most favorable isomers, aC
2v isomer with a dicoordinate oxygen atom, planar six-membered cycle, and one terminal fluorine atom and a pyramidalC
3v isomer with a tricoordinate oxygen atom and three bridging fluorine atoms, are almost degenerate in energy. The barriers
to rearrangements with the breaking of one fluorine bridge are no higher than 4 kcal mol−1, except for the pyramidalC
3v isomer (∼16 kcal mol−1). On the contrary, rearrangements with the breaking of the O−Be bond occur with overcoming of a high energy barrier (∼24
kcal mol−1). A planarD
3h isomer with a tricoordinate oxygen atom and linear O−Be−H fragments was found to be the most favorable for the OBe3H3
+ cation, a hydride analog of the OBe3F3
+ ion; the energies of the remaining five isomers are more than 25 kcal mol−1 higher.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 420–430, March, 1999. 相似文献
17.
A.K. Singh Puja Saxena Amit Panwar 《Journal of inclusion phenomena and macrocyclic chemistry》2006,54(3-4):299-305
Copper (II) complex of 2,4-dimethyl-1,5,9,12-tetraazacyclopentadeca-1,4-diene, [Me2(15)dieneN4] was synthesized and used in the fabrication of Cu2+ – selective ISE membrane in PVC matrix. The membrane having Cu(II) macrocyclic complex as electroactive material along with sodium tetraphenyl borate (NaTPB) as anion discriminator. Dibutyl phthalate (DBP) as plasticizer in poly(vinyl chloride) (PVC) matrix was prepared for the determination of Cu2+. The best performance was observed by the membrane having Cu(II) complex–PVC–NaTPB–DBP with composition 1:5:1:3. The sensor worked well over a concentration range 1.12 × 10−6 M–1.0 × 10−1 M between pH 2.1–6.2 and a fast response time 10±2 s and a lifetime of 6 months. Their performance in partially non-aqueous medium was found satisfactory. Electrodes exhibited excellent selectivity for Cu2+ ion over other mono-, di-, trivalent cations. It can also be used as indicator electrode in the potentiometric titration of Cu2+ against EDTA as well as in the determination of Cu2+ in real samples. 相似文献
18.
5,10,15,20-tetrakis(phenoxy acetic acid) porphyrin (PAAP) was covalently linked to Merrifield chloromethylated resin. Characterization
of PAAP and the modified polymeric matrix were performed by 1H NMR, FTIR and elemental analysis. The sorbent was used for the separation and enrichment of the d-electron metals (Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)) at pH 6–8 and of the f-electron metals U(VI) and Th(IV) at pH 4–5. The metals ions were preconcentrated with a concentration factor range of 115–215
and then determined by flame atomic absorption spectrometry or visible spectrophotometry using Arsenazo(III). The retained
metals were eluted with 2.0 mol L−1 HNO3 in the case of the d-electron metals and 0.1/0.25 mol L−1 HCl in the case of the f-electron metals. The procedure was validated by analyzing the NIST standard reference material 2709 (San Joaquin Soil).
Correspondence: Melek Merdivan, Chemistry Department, Faculty of Arts and Sciences, Dokuz Eylul University, 35160 Buca, Izmir,
Turkey 相似文献
19.
Hong Fashui Liu Chao Zheng Lei Wang Xuefeng Wu Kang Song Weiping Lü Shipeng Tao Ye Zhao Guiwen 《中国科学B辑(英文版)》2005,48(1):67-74
The complex of Rubisco and Rubisco activase from LaCl3
™, CeCl3
™ treated spinachin vivo is induced. SDS-PAGE result shows that the purified proteins from LaCl3
™, CeCl3
™ treated spinach have not only large and small subunits (55 kD, 14.4 kD) of Rubisco, but also two large subunits of 45 kD
and 41 kD near the large subunits of Rubisco. Native-PAGE shows that the purified proteins from LaCl3
™, CeCl3
™ treated spinach have not only a band of Rubisco (560 kD), but also a band of about 1100 kD, about twice distant from Rubisco,
which might be a complex of Rubisco and Rubisco activase. The purified enzyme activities from LaCl3
™, CeCl3
™ treated spinach are 1.8 and 2.8 times that of the control, the intensities of absorption and fluorescence are significantly
higher than that of the purified Rubisco from the control, and the total sulfhydryl groups and available sulfhydryl groups
are 36–39 ™SH per mol enzyme, 14–25 ™SH per mol enzyme more than those of the purified Rubisco from the control, respectively.
The CD spectra show that the secondary structure of the purified enzyme from LaCl3
™, CeCl3
™ treated spinach is very different from the control. The enzyme activities from LaCl3
™, CeCl3
™ treated spinachin vivo are 1.5 and 1.9 times those of the control. 相似文献
20.
The damped glycolytic oscillation phenomenon occurring in starved cells of the yeast Saccharomyces cerevisiae (NBRC 0565) was characterization for application to a toxicity bioassay. S. cerevisiae was grown under semi-anaerobic conditions. The transient oscillations were observed photometrically as the time course of
the fluorescent intensity of reduced pyridine nucleotide resulting from instantaneous addition of glucose to a cell suspension.
In this study, simple and reproducible conditions inducing damped oscillations were obtained by modifying a literature method.
For estimation of the wave shapes of the damped oscillations we used six indexes. To investigate the total reproducibility
as the averaged relative standard deviation (RSDav) for the six indexes obtained from the wave shapes, the damped oscillations were induced under the optimum conditions and
the RSDav values were calculated as 14% in a buffer cell suspension (n = 62) and 22% in a water cell suspension (n = 78). Finally, the effects of glucose concentration on the six indexes were examined, and all the indexes changed when the
glucose concentration was changed. Excellent correlations were obtained between the index of oscillation-state time and the
concentration of glucose in a buffer cell suspension (r = 0.9985, 0.5–250 mmol L−1, 10 points) and in a water cell suspension (r = 0.9989, 2.5 μmol L−1–250 mmol L−1, 12 points), respectively.
Figure Characterization of damped glycolytic oscillation, (a) typical shape, and (b) its estimation
Electronic supplementary material The online version of this article (doi:)contains supplementary material, which is available to authorized users. 相似文献