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At least 811 records · Page 45Linked to original sources
PubMed2006

Aqueous-aqueous two-phase systems composed of low molecular weight of polyethylene glycols and dextrans for counter-current chromatographic purification of proteins.

New aqueous-aqueous two-phase systems composed of relatively low molecular weight polymers such as polyethylene glycol (PEG) (Mr: 1000-4000) and dextran (Mr: 10,000 and 40,000) were evaluated for purification of proteins by counter-current chromatography (CCC). The compositions of aqueous two-phase systems were optimized by measuring parameters such as viscosity and volume ratio between the two phases. CCC purification of a glucosyltransferase (GTF) from Streptococcus mutans (SM) cell-lysate was successfully demonstrated with a 7.5% PEG 3350-10% dextran T40 system containing 10mM potassium phosphate buffer at pH 9.0. After CCC purification, both PEG and dextran contained in the CCC fractions were easily removed by ultrafiltration in a short period of time. The fractionated column contents containing GTF were analyzed by enzymatic activity as well as sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. The recovery of the enzyme from CCC fraction was over 95% as estimated by enzymatic activities.

Countercurrent Distribution↗
PubMed2006

The isolation of 1,2,3,4,6-penta-O-galloyl-beta-D-glucose from Acer truncatum Bunge by high-speed counter-current chromatography.

High-speed counter-current chromatography (HSCCC) was successfully used for the isolation and purification of 1,2,3,4,6-penta-O-galloyl-beta-D-glucose from the ethyl acetate extract of the leaves of Acer truncatum Bunge using a two-phase system composed of n-hexane-ethyl acetate-methanol-water at a volume ratio of (0.25:5:1:5, v/v/v/v) for the first time. Each injection of 80 mg crude extract yielded 7.25 mg of pure 1,2,3,4,6-penta-O-galloyl-beta-D-glucose. High-performance liquid chromatography (HPLC) analyses of the CCC fraction revealed that the purity of 1,2,3,4,6-penta-O-galloyl-beta-D- glucose was over 95%.

Acer↗
PubMed2004

Two glucosylated abscisic acid derivates from avocado seeds (Persea americana Mill. Lauraceae cv. Hass).

Phytochemical investigation of avocado seed material (Persea americana Mill., Lauraceae) resulted in the isolation of two glucosylated abscisic acid derivates. One of these was not known as a natural product and can be regarded as a potential 'missing link' in abscisic acid metabolism in plants. After fractionation by high-speed countercurrent chromatography, and multiple steps of column chromatography, structures were elucidated by 1D-, 2D-NMR, electrospray-MS to be the novel beta-d-glucoside of (1'S,6'R)-8'-hydroxyabscisic acid, and (1'R,3'R,5'R,8'S)-epi-dihydrophaseic acid beta-d-glucoside. Absolute configuration was determined by circulardichroism, optical rotation, and by NOE experiments.

Abscisic Acid↗
PubMed2001

Effect of counter-anion concentration on retention in high-performance liquid chromatography of protonated basic analytes.

The influence of acid and salt concentration in the mobile phase on the retention of basic analytes has been studied. An increase in the retention of fully protonated analytes with increasing the concentration of inorganic additives was found. The addition of salt, such as perchlorate, trifluoroacetate, and phosphate, leads to the increase of retention for fully protonated analytes while mobile phase pH remains constant. The observed effect was attributed to the interaction of protonated analytes with the counter-anion of acid or salt, which leads to the disruption of the analyte solvation shell and the increase of its hydrophobicity and corresponding increase of retention. A mathematical model for the description of the influence of counter-anion concentration on analyte retention is proposed.

Anions↗
PubMed1977

Preparative countercurrent chromatography with a slowly rotating helical tube.

The capability of a simple countercurrent chromatographic scheme for obtaining high-resolution preparative-scale separations was demonstrated with the separations of a series of dinitrophenyl (DNP) amino acids and peptides. Basic studies on stationary phase retention and partition efficiency with a low-viscosity chloroform-acetic acid-0.1 N hydrochloric acid (2:2:1) phase system together with the results previously obtained with a vascous n-butanol system suggest a general applicability of low-interfacial tension phase systems by the present method.

Amino Acids↗
PubMed1988

Multi-stage mixer-settler planet centrifuge. Preliminary studies on partition of macromolecules with organic-aqueous and aqueous-aqueous two-phase solvent systems.

A rotary-seal-free planetary centrifuge holds a separation column which consists of multiple partition units (ca. 200) connected in series with transfer tubes. In the cavity of each partition unit the transfer tube extends to form a mixer which vibrates to stir the contents under an oscillating force field generated by the planetary motion of the centrifuge. Consequently, solutes locally introduced at the inlet of the column are subjected to an efficient partition process in each partition unit and separated according to their partition coefficients. The mixer tube equipped with a flexible silicone rubber joint was found to produce excellent results for partition with viscous polymer phase systems. The capability of the method was demonstrated on separation of cytochrome c and lysozyme using a PEG-aqueous dibasic potassium phosphate-aqueous two-phase solvent system.

Animals↗
PubMed1987

Counter-current chromatographic purification of [D-Ala]peptide T amide.

A recently proposed octapeptide, [D-Ala]peptide T amide (D-Ala-Ser-Thr-Thr-Thr-Asn-Tyr-Thr-NH2), has been shown to bind to the CD4 receptor on human T-cell lymphocytes and block human immunodeficiency viral infectivity. This peptide may not only be itself a promising therapeutic for the disease of AIDS (acquired immune deficiency syndrome), but might open a new avenue of research towards more efficacious drugs. Accordingly, a counter-current chromatography system is here presented, utilizing the Ito flow-through coil planet centrifuge (solvent system, 1% trifluoroacetic acid-n-butanol (1:1), upper phase mobile) which allows facile preparative purification of [D-Ala]peptide T amide. The method may be applicable to purifying analogues of [D-Ala]peptide T amide as they are developed.

Chromatography, High Pressure Liquid↗
PubMed2001

Separation of apple procyanidins into different degrees of polymerization by high-speed counter-current chromatography.

Apple procyanidins were fractionated by high-speed counter-current chromatography in a one-step operation from apple condensed tannins using a type-J multilayer coil planet centrifuge. The separation of procyanidins was performed with a two-phase solvent system composed of methyl acetate-water (1:1) by eluting the upper phase at a flow-rate of 1.0 ml/min. Each fraction was examined by time-of-flight mass spectrometry. Procyanidins were separated according to their degrees of polymerization.

Biflavonoids↗
PubMed2001

Preparative isolation and purification of acteoside and 2'-acetyl acteoside from Cistanches salsa (C.A. Mey.) G. Beck by high-speed counter-current chromatography.

High-speed counter-current chromatography (HSCCC) was applied to the separation and purification of phenylethanoid glycosides (PhGs) acteoside and 2'-acetylacteoside from Cistanches salsa (C.A. Mey) G. Beck with a quaternary two-phase solvent system composed of ethyl acetate-n-butanol-ethanol-water (4:0.6:0.6:5, v/v). HPLC analyses of the CCC fractions revealed that the two main PhGs were over 98% purity. Their chemical structures were identified by 1H NMR, 13C NMR and MS.

Chromatography, High Pressure Liquid↗
PubMed2001

Counter-current chromatographic separation of glycoprotein components from Morchella esculenta (L.) with a polymer phase system by a cross-axis coil planet centrifuge.

Using a cross-axis coil planet centrifuge, glycoproteins were separated from fermentation media of Morchella esculenta (L.) by high-speed counter-current chromatography. The performance of the apparatus was optimized with four standard proteins including pepsin, lysozyme, ovalbumin and hemoglobin and a polymer phase system composed of 12.5% (w/w) polyethylene glycol 8000 and 25% (w/w) potassium phosphate in distilled water at various pH values. Separations were performed by eluting the lower phosphate-rich phase at a flow-rate of 1.0 ml/min. Under the optimized conditions three glycoprotein components in Morchella esculenta (L.) were resolved within 6 h.

Agaricales↗
PubMed2001

Preparative separation of the naphthopyranone glycosides by high-speed counter-current chromatography.

High-speed counter-current chromatography was applied to the preparative separation and purification of naphthopyranone glycosides from a crude 70% ethanolic extract of the capitula of Paepalanthus microphyllus. The solvent system used was composed of water-ethanol-ethyl acetate-hexane (10:4:10:4, v/v). This technique led to the separation of four different naphthopyranone glycosides in pure form in only 7 h.

Chromatography, High Pressure Liquid↗
PubMed2001

Large-scale separation of resveratrol, anthraglycoside A and anthraglycoside B from Polygonum cuspidatum Sieb. et Zucc by high-speed counter-current chromatography.

High-speed counter-current chromatography was successfully applied to the large-scale separation of resveratrol, anthraglycoside A and anthraglycoside B from the crude extract of Polygonum cuspidatum Sieb. et Zucc using a two-phase solvent system composed of chloroform, methanol and water. Resveratrol, anthraglycoside A and anthraglycoside B were separated from multigram quantities (5 g) of crude extract of P. cuspidatum. The separation yielded 200 mg to 1 g of these three compounds each at over 98% purity as determined by HPLC. The chemical structures of these components were identified by nuclear magnetic resonance (NMR) and MS.

Anthracenes↗