Hydrophobic chromatography

Hydrophobic Interaction Chromatography. Hydrophobic interactions of solutes with a stationary phase result in thek adsorption on neutral or mildly hydrophobic stationary phases. The solutes are adsorbed at a high salt concentration, and then desorbed in order of increasing surface hydrophobicity, in a decreasing kosmotrope gradient. This characteristic follows the order of the lyotropic series for the anions ... 

The cytokine-inducing active fraction (QM-A) was prepared from E, hirae ATCC 9790 cells as described [9]. Briefly, the bacterial cells (922 g) were delipidated and extracted with hot phenol-water, and the crude extract was digested with RNase and DNase, to give crude LTA fractions. The crude LTA was subjected to two successive chromatography, hydrophobic interaction... 

Ion exchange chromatography, hydrophobic interaction chromatography (HlC), and affinity chromatography (AC) show some similarities concerning practical realization therefore, most of the hints given for lEC are applicable for HlC and AC. Examples for AC are given in Protocols 3.6.2.4 (biospecific desorption) and 3.6.2.5 (elution by partial denaturation). 

Ion-exchange chromatography Hydrophobic Interaction chromatography Affinity chromatography... 

Dyes are relatively complex organic structures inducing different concomitant interactions. They contains most of the time sulfonate groups with a strong ionic effect they are constituted of multiaromatic rings with donor-acceptor effect described as major contribution in chromatography hydrophobic interactions are also promoted by their chemical structure. 

Chromatography hydrophobicity index Dimethyl sulfoxide Fetal calf serum... 

Affinity or ion-exchange chromatography Intermediate purilicalion Ion-exchange chromatography Hydrophobic interaction chromatography Polishing... 

High-pressure homogenization, bead mills, sonication, enzymatic treatments Filtration (micro-, ultra-, nano-filtration), precipitation, solvent extraction, ion exchange, size exclusion, affinity chromatography Hydrophobic interaction/reversed-phase chromatography... 

Polarity Adsorption chromatography Reverse-phase chromatography Hydrophobic interaction chromatography... 

Mevalonate kinase (EC 2.7.1.36) phosphorylates mevalonic acid, the NADPH-reduced form of HMG-CoA. The reaction is ATP and Mg dependent. The enzyme was purified from a C. roseus cell suspension culture, in which, after induction a specific activity of 1.5 nkat/mg protein is found [12]. The purification protocol comprised ion-exchange chromatography, hydrophobic interaction chromatography and gel filtration. By gel filtration an M,. of 105,000 was found for mevalonate kinase. 

Proteins can be separated by any of a number of different HPLC techniques size-exclusion chromatography, ion-exchange chromatography, hydrophobic interaction chromatography, or reversed-phase chromatography. Affinity chromatography is not usu y considered to be an HPLC technique, and is not covered in this book. 

Such characterization investigations could mostly be performed routinely, whereas the purification procedures for each particular enzyme needed to be developed and optimized from the very beginning. With biochemical methods such as a combination of ammonium sulfate fractionation," ion exchange chromatography," gel filtration," adsorption chromatography, hydrophobic interaction chromatography, etc. an entire array of purification methods was available and employed successfully over several years for enzyme purification. 

The hydrophobicity of a stationary phase is responsible for the retention of the analytes. This is mainly determined by the specific surface area and the carbon content, discussed earlier. But as far as the selectivity is concerned, in reversed-phase (RP)-chromatography hydrophobic interactions usually play a much less important role than is generally believed, ionic/polar interactions, and steric aspects - if they come into play - are more dominant factors. Only by means of these influencing factors can analytes be differentiated. This is also the reason why a correlation between retention and selectivity factors is rather seldom observed, discussed later. Such a correlation may at the best be expected from a uniform RP mechanism in which van der Waals interactions predominate, which is seldom the case (homologous series or simple pairs of analytes such as toluene/ethyl benzene). This is because the molecules to be analyzed mostly have groups that are capable of ionic/polar interactions. Even with hydrophobic aromatic compounds, we are dealing with induced dipoles in addition, the polarity may increase through resonance. 

Reversed-phase chromatography Hydrophobic complex formation Hydrophobicity... 

Polymeric sorbents Polymeric resins BET 300- llOOm /g i e a= 10 10 80 Waste water treatment (ion exchange) Chromatography Hydrophobicity Regeneration often easily... 

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