Affinity ultrafiltration

Zhang, H., Pan, Y Affinity ultrafiltration of DNA topoisomerases-targeted compounds determined with HPLC/ESI-MS for drug candidate screening. J. Zhqiang Univ. Sci. 2004, 5, 900-905. 

Romero J, Zydney AL (2002), Affinity ultrafiltration effects of ligand binding on selectivity and process optimization, Biotechnol. Bioeng. 77 256-265. 

Plastic microdevices for high-throughput screening with MS detection were also prepared for detection of aflatoxins and barbiturates. These devices incorporated concentration techniques interfaced with electrospray ionization MS (ESI-MS) through capillaries [2], The microfluidic device for aflatoxin detection employed an affinity dialysis technique, in which a poly (vinylidene fluoride) (PVDF) membrane was incorporated in the microchip between two channels. Small molecules were dialyzed from the aflatoxin/antibody complexes, which were then analyzed by MS. A similar device was used for concentrating barbiturate/antibody complexes using an affinity ultrafiltration technique. A barbiturate solution was mixed with antibodies and then flowed into the device, where uncomplexed barbiturates were removed by filtration. The antibody complex was then dissociated and electrokinetically mobilized for MS analysis. In each case, the affinity preconcentration improved the sensitivity by at least one to two orders of magnitude over previously reported detection limits. 

Glatz Z., Affinity ultrafiltration BOLKOVIN, Chemicke Listy, 94, 490 93, 2000. 

The principles of affinity chromatography can be combined with other operations of purification to improve them (Labrou and Clonis 1994). Affinity partition combines the selectivity of affinity ligation with aqueous two-phase extraction (Kamihira et al. 1992 Kohler et al. 1991) and has been successfully employed in enzyme recovery and purification (Johansson and Tjerneld 1989 Schustolla et al. 1992) obtaining impressive increases in the partition coefficient (Eq. 2.16) and therefore in yield of enzyme recovery (Eq. 2.17). Affinity partition has also been combined with membrane separation (affinity ultrafiltration), where a soluble... 

Fickers P, Ongena M, Destain J et al. (2006) Production and down-stream processing of an extracellular lipase from the yeast Yarrowia lipolytica. Enzyme Microb Technol 38(6) 756-759 FUippusson H, Sigmundsson K (1992) An affinity ultrafiltration system for the purification of trypsin. Ann NY Acad Sd 672 613-618... 

Male KB, Nguyen AL, Luong JHT (1990) Isolation of urokinase by affinity ultrafiltration. Biotechnol Bioeng 35(l) 87-93... 

Romero J, Zydney AL (2002) Affinity ultrafiltration effects of ligand binding on selectivity and process optimization. Biotechnol Bioeng 77(3) 256-265 Roopesh K, Ramachandran S, Nampoothiri KM et al. (2006) Comparison of phytase production on wheat bran and oilcakes in solid-state fermentation by Mucor racemosus. Biores Technol 97(3) 506-511... 

We have developed a high throughput ultrafiltration affinity screening method coupled to MS (affinity selection/mass spectrometry ASMS), which works with any soluble target and small molecule library (including natural products). ASMS is amenable to parallelization, efficient and robust enough to allow study... 

The general method for ASMS is shown in Fig. 4.1. In ASMS, the target concentration is generally set at 5-10 xM, so that at equilibrium, ligands with affinities of no weaker than Ku 10 xM will be significantly bound and, therefore, retained in the ultrafiltration steps. The minimal concentration of each small molecule is dictated by the eventual need to detect ligands by mass spectrometry after several cycles of ultrafiltration and subsequent extraction. In order to ensure detection just above baseline for the vast majority of compounds, which vary in inherent ionization properties and efficiency of mass spectrometric visibility, the starting compound concentration is set at 1.5 pM per compound. The mixture... 

Both round 0 data (before affinity selection) and round 3 data (after three rounds of affinity selection) are shown, where round 0 represents a sampling prior to any ultrafiltration. Round 0 and round 3 samples undergo identical denaturation/solvent extraction procedures. Data were generated... 

Pulsed ultrafiltration MS (PUF-MS) represents an inline high throughput affinity screening method with a variety of potential uses in the discovery and development of pharmaceuticals [22]. The in-line combination of solution-phase equilibration, ultrafiltration, and electrospray liquid chromatography mass spectrometry (LC-ESI-MS) facilitates the identification of high affinity target-specific... 

R. B. Ultrafiltration tandem mass spectrometry of estrogens for characterization of structure and affinity for human estrogen receptors. J. Am. Soc. Mass Spectrom. 2005, 16, 271-279. 

Figure 3.17. A likely purification procedure for tPA produced in recombinant E. coli cells. The heterologous product accumulates intracellularly in the form of inclusion bodies. In this particular procedure, an ultrafiltration step is introduced on several occasions to concentrate the product stream, particularly prior to application to chromatographic columns. Lysine affinity chromatography (Lys-chromatography) is employed as tPA is known to bind immobilized lysine molecules. Adapted with permission from Datar et al. (1993)...

Serum Br, Cu, Fe, I, Mn, Se, Rb, V and Zn Cu, Zn Zn A1 Neutron activation GFAAS, Immunonephelometry GFAAS, Affinity chromatography, Kinetic immunoturbidimetry GFAAS, Ultrafiltration Detailed examination of the behaviour of the elements during fractionation and the effect of contamination in the reagents and equipments 41) 36) 42) 43)... 

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