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Gisela Peters 《Fresenius' Journal of Analytical Chemistry》1966,217(6):453-454
Ohne Zusammenfassung 相似文献
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Because protein folding dynamics are heavily overdamped, Kramers theory predicts the rate of folding to scale inversely with the reaction friction, which is usually interpreted to mean the solvent viscosity. This does not mean, however, that the speed of folding can increase without limit as solvent viscosity decreases. We show that, in a sufficiently fast-folding protein, the folding speed approaches a finite limit at low solvent viscosity, indicating a reaction controlled by internal friction. 相似文献
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Measurement of intracellular Ca2+ changes using novel caged cyclic nucleotides and confocal laser scanning microscopy. 总被引:1,自引:0,他引:1
The intention of this study is to explore the applicability of confocal microscopy in conjunction with the use of caged cyclic nucleotide derivatives. The methodological potential of UV laser confocal microscopy has been assessed. It is shown that illumination of a single cell or a small area of a single cell is possible, whereby the intracelluar Ca2+ signal is measured at illuminated and non-illuminated cells. Such measurements do not have a high time resolution because of the specific system parameters. However, with an N2 pulse laser (not part of the standard microscope set-up), Ca2+ signals with a time resolution of around 100 ms have been measured. This facilitates investigation of the kinetics of Ca2+ influx. Intracellular Ca2+ measurements at HEK293 and sperm cells have been made here. For sperm cells the advantages of confocal microscopy are best evidenced in conjunction with the use of caged cyclic nucleotides; a cyclic nucleotide-gated Ca2+ influx at the tail of these cells has thereby been demonstrated for the first time. 相似文献
58.
V. L. E. Simonsen L. Nørskov A. Hagen K. Kammer Hansen 《Journal of Solid State Electrochemistry》2009,13(10):1529-1534
The series La2 − x
Sr
x
NiO4 (x = 0.0, 0.05, 0.15, 0.25, 0.35, and 1.0) was tested for functionality as electrode materials for direct electrochemical reduction
of NO. The materials were tested using cyclic voltammetry in 1% NO and 10% O2 in Ar on a cone-shaped electrode. The best materials for the electrochemical reduction of NO are La2NiO4 and LaSrNiO4, which have current densities for NO reduction 1.82 and 7.09 times higher, respectively, than for O2 at 400 °C. Increasing the temperature decreased the ability to reduce NO before O2 while the activity increased. The adsorbed species during direct decomposition was attempted, clarified using X-ray absorption
near-edge structure experiments and thermogravimetry, but no conclusive results were obtained. 相似文献
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Udit AK Hagen KD Goldman PJ Star A Gillan JM Gray HB Hill MG 《Journal of the American Chemical Society》2006,128(31):10320-10325
We report analyses of electrochemical and spectroscopic measurements on cytochrome P450 BM3 (BM3) in didodecyldimethylammonium bromide (DDAB) surfactant films. Electronic absorption spectra of BM3-DDAB films on silica slides reveal the characteristic low-spin FeIII heme absorption maximum at 418 nm. A prominent peak in the absorption spectrum of BM3 FeII-CO in a DDAB dispersion is at 448 nm; in spectra of aged samples, a shoulder at approximately 420 nm is present. Infrared absorption spectra of the BM3 FeII-CO complex in DDAB dispersions feature a time-dependent shift of the carbonyl stretching frequency from 1950 to 2080 cm(-1). Voltammetry of BM3-DDAB films on graphite electrodes gave the following results: FeIII/II E(1/2) at -260 mV (vs SCE), approximately 300 mV positive of the value measured in solution; DeltaS degrees (rc), DeltaS degrees , and DeltaH degrees values for water-ligated BM3 in DDAB are -98 J mol(-1) K(-1), -163 J mol(-1) K(-1), and -47 kJ mol(-1), respectively; values for the imidazole-ligated enzyme are -8 J mol(-1) K(-1), -73 J mol(-1) K(-1), and -21 kJ mol(-1). Taken together, the data suggest that BM3 adopts a compact conformation within DDAB that in turn strengthens hydrogen bonding interactions with the heme axial cysteine, producing a P420-like species with decreased electron density around the metal center. 相似文献
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