Real-time kinetic measurements

Gerder, A., Grosclaude, J., Strasburger, C. J., Nir, S., and Djiane, J. (1996). Real-time kinetic measurements of the interactions between lactogenic hormones and prolactin-receptor extracellular domains from several species support the model of hormone-induced transient receptor dimerization. J. Biol. Ghent. 271(40), 24482-24491. 

K.M. Parkhurst, M. Brenowitz and L.J. Parkhurst. Simultaneous binding and bending of promoter DNA by the TATA binding protein real time kinetic measurements. Biochemistry 35 (1996) 7459-65. 

Real-Time Kinetic Measurements and Determination of andk.. ... 

In a real-time spectroellipsometric measurement in which the kinetics of a-Si H deposition is studied, trajectories are recorded in the A-4 plane at various photon energies between 2 and 4 eV. These trajectories can be simulated and fitted to models that represent the growing a-Si H layer. Canillas et al. [347] have made a detailed study of the deposition of the first few layers of a-Si H on a NiCr/glass substrate. Similar results are obtained for a c-Si substrate. They have proposed several models to explain the data. One possible model is the hemispherical nu-cleation model, which describes a hexagonal network of spherical a-Si H nuclei located at an average distance d between them. The growth is represented by an... 

The background problem can be further overcome when using a surface-confined fluorescence excitation and detection scheme at a certain angle of incident light, total internal reflection (TIR) occurs at the interface of a dense (e.g. quartz) and less dense (e.g. water) medium. An evanescent wave is generated which penetrates into the less dense medium and decays exponentially. Optical detection of the binding event is restricted to the penetration depth of the evanescent field and thus to the surface-bound molecules. Fluorescence from unbound molecules in the bulk solution is not detected. In contrast to standard fluorescence scanners, which detect the fluorescence after hybridization, evanescent wave technology allows the measurement of real-time kinetics (www.zeptosens.com, www.affinity-sensors.com). 

The PHSS method of real-time H2S measurement allows for investigating the potentially complex H2S kinetic responses of organs, tissues, cells, and mitochondria as levels of 02 and NO as well as metabolic state are adjusted within physiological limits. Kinetic changes in H2S concentration continuously reported by the PHSS, which are not seen with other H2S measurement techniques, suggest potentially complex interactions of H2S production and consumption mechanisms. H2S may likely exist as a cellular pool of free and labile persulfides able to rapidly respond to redox challenges with production and consumption pathways that operate to maintain the pool. This possible scenario reinforces the need for the PHSS as a valuable tool to provide a continual report of H2S throughout the course of an experimental treatment or to accurately determine H2S levels in situ. 

The mby fluorescence method allows us to perform pressure measurements in a short time scale (1-10 s), providing a real-time access for pressure control comparing to the time scale of many solid-state chemical processes. As a matter of fact, real-time pressure measurements are necessary when studying kinetic processes [117], but it is also important to minimize the laser power used for measuring the mby fluorescence in order to avoid undesired photochemical effects on the sample, whenever these are possible. In the case of IR absorption studies, which are commonly used for kinetic purposes, the advantage of using the mby fluorescence method, once photochemical effects are prevented, with respect to the employment of vibrational gauges is that no additional absorption bands are introduced in the IR spectmm. 

Cladera J, O Shea P. Generic techniques for fluorescence measurements of protein-ligand interactions real-time kinetics and spatial imaging. In Protein-Ligand Interactions. Harding SE, Chowdery BZ, eds. 2001. Oxford University Press, UK. pp. 169-200. 

Inhibitor kinetics The IC50 determinations described herein provide a simple method of comparing protease inhibitors. However, it may be desirable to characterize the interactions of inhibitors with the enzyme in more detail. Both the chromogenic and fluorescence assays can be read in kinetics mode on the machines described to give real-time rate measurements for use in determining kinetic parameters. 

Ease and speed of measurement often allows real-time kinetics to be followed. 

Real-time spectroscopic methods can be used to measure the binding, dissociation, and internalization of fluorescent ligands with cell-surface receptors on cells and membranes. The time resolution available in these methods is sufficient to permit a detailed analysis of complex processes involved in cell activation, particularly receptor-G protein dynamics. A description of the kinetics and thermodynamics of these processes will contribute to our understanding of the basis of stimulus potency and efficacy. 

From the examples given above it is clear that the development of a novel approach for real time measurements of the dissociation kinetics of reaction intermediates would greatly assist the unravelling of complex multistep processes associated with the transformation of even simple molecules at transition metal centers. While techniques are available for such measurements over a limited range of times, none of the methods are sufficiently general to be useful for extensive measurements. 

Atomic metal ion-hydrocarbon reactions bond dissociation energies for fragments, 15,16t endothermic reactions, 13,15,17f Atomic transition metal ion reactions development of approach for real-time measurements of dissociation kinetics, 39 ion beam apparatus, 12,14f studies of... 

The most common methodology for measuring fast kinetics in real time is to perturb a system at equilibrium for a time duration that is much shorter than the relaxation kinetics that follow perturbation. This perturbation can be achieved by changing the concentration of chemicals through fast mixing (stopped-flow), changing the temperature of the solution (temperature jump), simultaneously changing the... 

S.S. Cherukupalli, S.E. Gottlieb and A.A. Ogale, Real-time Raman spectroscopic measurement of crystallization kinetics and its effect on the morphology and properties of polyolefin blown films, J. Appl. Polym. Sci., 98, 1740-1747 (2005). 

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