Reaction kinetics and kinetic processes in modern liquid chromatographic reactors

Jeng, Chawn-Ying; Langer, Stanley H.

doi:10.1016/0021-9673(92)80002-c

Cited by 37 publications

(14 citation statements)

References 142 publications

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“…Slow interconverting cis/trans isomers were shown to lead to peak multiplicity in RP-HPLC [21,22] and capillary electrophoresis [23,24] since there is a difference in the migration time of the isomers. Differentiating minor peaks of c&/trans conformers from those resulting from impurities usually inherent in solid phase peptide synthesis becomes increasingly difficult when chain length increases.…”

Section: Conformational Homogeneitymentioning

confidence: 99%

Extended binding sites of cyclophilin as revealed by the interaction with HIV‐1 Gag polyprotein derived oligopeptides

et al. 1996

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Oligopeptides derived from the gag polyprotein (Pr55 gag) of human immunodeficiency virus type 1 (HIV-1) segment were used to evaluate the extension of the putative binding region for the complex of Pr55 gag and the human cytosolic peptidyl prolyl cis/trans isomerase (PPIase) 18 kDa cyclophilin (Cypl8). Five N-terminally acetylated, C-terminally amidated oligopeptides containing one (HIV-1 Gag218-224; 1), two (HIV-1 Gag 21s-226 and HIV-1 Gag217-224; 2 and 3, respectively), three (HIV-I Gag217-226; 4) or four (HIV-1 Gag213-237; 5) proline residues were synthesized. Using competition experiments with a standard substrate the binding affinities to Cypl8 of the synthesized peptides were determined. The ICs0 value of 184 ~M for the 25-mer peptide 5 was fivefold or more lower than those of the peptides 1--4 lacking one or more prolines. Failure of competition in assays containing enzymes of other PPlase families by millimolar concentrations of 5 revealed a Cyp18 specific interaction involving the active site of the enzyme. In its far UV circular dichroism, aqueous solutions of 5 display properties of random coil conformation, but spectra were also consistent with a small contribution of proline specific secondary structures. However, a proline-rich peptide typical of forming left-handed polyproline II helices did not compete for the active site of Cypl8. The results demonstrate that the putative binding region of HIV-1 gag polyprotein has a certain degree of binding affinity to the PPIase site of Cypl8, and may add a previously unrecognized topological component to the known subsite specificity of cyciophilins.

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Section: Conformational Homogeneitymentioning

confidence: 99%

Extended binding sites of cyclophilin as revealed by the interaction with HIV‐1 Gag polyprotein derived oligopeptides

et al. 1996

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“…Some recent publications describe the results on investigation of autocatalytic reactions [135], first-order reversible reactions [136], and estimation of enantioselectivity [137,138]. It is beyond the scope of this chapter to discuss the details, but the interested reader is referred to an overview published by Jeng and Langer [139]. Most publications dealing with chromatographic reactors focus on theoretical issues of this very complex system.…”

Section: Reactor Typesmentioning

confidence: 98%

Chromatographic Reactors Based on Biological Activity

Podgornik

Tennikova

2002

Advances in Biochemical Engineering/Biotechnology

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In the last decade there were many papers published on the study of enzyme catalyzed reactions performed in so-called chromatographic reactors. The attractive feature of such systems is that during the course of the reaction the compounds are already separated, which can drive the reaction beyond the thermodynamic equilibrium as well as remove putative inhibitors. In this chapter, an overview of such chromatographic bioreactor systems is given. Besides, some immobilization techniques to improve enzyme activity are discussed together with modern chromatographic supports with improved hydrodynamic characteristics to be used in this context.

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“…Fortunately, as will be demonstrated in this work, the performance of many of today's gas chromatographs and columns allows GCRs to behave like ICRs under a wide range of experimental conditions, thus greatly simplifying the mathematical treatment of many reactions. (Note that in liquid chromatographic reactors (LCRs) [12,13] and in systems where more complicated chemical kinetics are involved [14,15], ICR assumptions may not be used. In these cases, numerical methods are sometimes necessary to extract the kinetic information [16].…”

Section: On-column Decomposition Of Tert-butyl Peroxidementioning

confidence: 99%

Thermal decomposition of tert‐butyl peroxide in a gas chromatographic reactor: A comparison of kinetic approaches

Skrdla

2004

Int J of Chemical Kinetics

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The thermal decomposition of tert-butyl peroxide is investigated utilizing both the column and the injection port of a commercial gas chromatograph (GC) as chemical reactors. Using the injector liner as the reactor, the chromatographic peak areas of the reactant, measured at various injector temperatures, are used in the determination of the activation energy of the decomposition (E a ). With the column serving as the reactor, both the reactant peak areas and the product peak shapes are similarly utilized for this purpose. Values of E a obtained using different mathematical treatments for each of the three approaches are found to range from 115 to 164 kJ/mol. Of these methods, the column reactor approach utilizing peak area measurements (referred to as PACR, for "peak area, column reactor") is found to be far superior in terms of its speed, robustness, and its accuracy in determining E a . The PACR method's effectiveness can be largely attributed to the mathematical treatment that is described in the approach. C

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Reaction kinetics and kinetic processes in modern liquid chromatographic reactors

Cited by 37 publications

References 142 publications

Extended binding sites of cyclophilin as revealed by the interaction with HIV‐1 Gag polyprotein derived oligopeptides

Extended binding sites of cyclophilin as revealed by the interaction with HIV‐1 Gag polyprotein derived oligopeptides

Chromatographic Reactors Based on Biological Activity

Thermal decomposition of tert‐butyl peroxide in a gas chromatographic reactor: A comparison of kinetic approaches

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