Chromatographic fractionation

During the isolation of inhibin from foUicular fluid, some chromatographic fractions stimulated FSH release from cultured anterior pituitary cells, suggesting the existence of FSH releasing proteins (FRPs). Two FRPs, given the generic term activins, were subsequentiy isolated (131,132). One is composed of two disulfide-finked P-A subunits (activin A) the other consists of similarly finked P-A and P-B subunits (activin AB). 

The combined acetone extracts were extracted six times with one-fourth volume of ethylene dichloride and the ethylene dichloride extract was evaporated under vacuum to leave the steroid residue. This steroid residue was taken up in a minimum of methylene chloride and applied to the top of a column packed with 30 grams of silica which had been previously triturated with 21 ml of ethylene glycol. Then various developing mixtures, saturated with ethylene glycol, were passed over the column. Cuts were made as each steroid was eluted as determined by the lowering of the absorption of light at 240 mp on the automatic chromatographic fraction cutter. 

The molecular masses may be smaller depending on the time of harvest and on the selection of chromatographic fractions during purification. 

Fig. 2a-c. Electron micrographs of the chromatographic fractions (a) concentrated culture fluid containing rotaviruses ( x 30000), (b) purified rotaviruses (fraction 1, Fig. 1, x 50000), (c) other components of culture fluid (fraction 3, Fig. 1, x 30000) [32]... 

Chromatographic fractions, glucuronide fractions A, B, and C were separated by reversed-phase chromatography. 

In the absence of adsorption, inclusion, or exclusion, a polymer is fractionated on a GPC column according to the hydrodynamic volume.40138 The hydrodynamic volume is a function of monomer identity, as well as polymer molecular weight, branching, and cross-linking. The polymer chains in any given chromatographic fraction have roughly the same hydrodynamic volume. 

Allelochemic effects of aquatic macrophytes on algae are discussed. Bloassays of chromatographic fractions from Eleocharls mlcrocarpa Torr. Indicate that oxygenated fatty acids are the causative agents. Methods of Isolation of these materials from aquatic macrophytes and from natural waters are described. Purification and structure determinations show that prominent components of the fraction are C q tri-hydroxycydopentyl and hydroxycydopentenone... 

Breci, L., Hattrup, E., Keeler, M., Letarte, J., Johnson, R., Haynes, PA. (2005). Comprehensive proteomics in yeast using chromatographic fractionation, gas phase fractionation, protein gel electrophoresis, and isoelectric focusing. Proteomics 5, 2018-2028. 

To resolve the linear oligomer fractions, Weidner et al. (2004) proposed an alternative approach. He used the combination of LCCC and MALDI-TOF to identify the different functionalities. Weidner performed a separation according to chemical composition by LCCC, and used a spray interface (LC-Transform from LabConnections) to deposit the chromatographic fractions on a MALDI-TOF target. In the second step, each individual... 

Procedure Purslane seeds were collected from crop fields near Naples. Five hundred seeds were sown in 10 Petri dishes (0 =90 mm), containing 5 layers of Whatman filter paper impregnated with 7 ml of water (control) or 7 ml rue infusion/chromatographic fractions or isolated compounds as per treatment. Thereafter, daily 3 ml water was added to each Petri plate. Germination conditions were 30 1°C with a continuous light of 25 4,E/m2/... 

Use of dimethoxydiphenylsilane in combination with N,N-dimethylformamide-p-toluenesulfonic acid to introduce silicon into the sucrose molecule has been exploited.27 On treatment with this combination of reagents, sucrose gave, after chromatographic fractionation of the acetylated mixture, 3,4,6,3, 4, 6 -hexa-0-acetyl-2,l -0-(diphenylsilyl)sucrose (10) and 3,4,3, 4 -tetra-0-acetyl-2,l 6,6 -di-0-(diphenylsilyl)sucrose (33) in 45 and 10% yield, respectively.27 With a view to introducing other heteroatoms, such as phosphorus or nitrogen, into the sucrose molecule, such reagents as dimethoxy-phenylphosphine, N,N-dimethylformamide dimethyl acetal, and 3,3-dimethoxypropylamine in combination with 2V,N-dimethylfor-mamide-p-toluenesulfonic acid are of interest. 

L. Breci, E. Hattrup, M. Keeler, J. Letarte, R. Johnson, and P. A. Haynes. Comprehensive Proteomics in Yeast Using Chromatographic Fractionation, Gas Phase Fractionation, Protein Gel Electrophoresis, and Isoelectric Focusing. Proteomics, 5(2005) 2018-2028. 

Chromatographic fractionation upon percolation is expected to be an extremely efficient way of changing relative distributions of trace elements. 

Carel, A. B. and Perkins, G. Analyt. Chim. 34 (1966) 83. Gas chromatographic fractionation as a supplement and replacement for laboratory distillation. 

Coprinus micaceus is abrmdant in the prairie region of Canada and is an edible mushroom. The methanohc extract of C. micaceus exhibited anti-bacterial activity against A. faecalis, S. aureus, Corynebacterium xerosis and E. coli at the concentration of 250 pg/ml in a preliminary anti-bacterial screening assay. A chromatographic fractionation of methanohc extract of this mushroom subsequently resulted in the isolation of a new bioactive sterol, micaceol (12). 

In Chapter 6, an attempt was made to identify suspect physiological cross-links, tentatively assigned from HPLC dafa, in addition to those already established in literature. Two novel cross-links, denoted chromatographic fractions IV and V-2, were purified from bovine root dentin, and the structure of V-2 was elucidated. During the analysis of human denfin as described in Chapter 5, V-2 appeared below detection level. A peak was observed for IV. Part of the material with the same retention as IV was not retained on cellulose in butanol/acetic acid/water = 4 1 1 (vol.). Co-elution of a non-cross-linking amino acid with IV could therefore not be excluded, and the results were omitted. 

The roots of the misidentified plant material Ipomoea murucoides were dried, pulverized, and macerated in chloroform. In reality, the analyzed plant material was /. arborescens as revealed by its chemistry which proved to be totally different from that identified for 7. murucoides (63), when the latter was fractionated by column chromatography. The basic hydrolysis of the resinous chromatographic fractions of this sample produced the same glycosidic acid derivative ultimately found in I. arborescens, i.e., murucinic acid (hexadecanoic acid, (115)-[((9-)S-d-... 

Separation of dibenzothiophene derivatives from petroleum oil fractions has been achieved by integrated approaches in which fractionating processes such as isothermal distillation, vacuum fractionation, and molecular distillation have been combined with spectroscopic methods including mass spectrometry and NMR spectroscopy. " Dibenzothiophenes have also been concentrated in sharp chromatographic fractions obtained, for example, by, alumina gel percolation, and have been detected by gas chromatography. Gas chromatography has also been used to... 

The third analysis is by infrared absorption spectrophotometry. This classical technique is often overlooked in today s mass-spectrometry dominated laboratory, but still remains a powerful tool which provides considerable information at moderate cost. Infrared spectra of the seven chromatographic fractions may be used to confirm... 

Figure 4. Liquid chromatographic fractions vs. class types...

At each stage, the location of the labelled material was followed by LSC of chromatographic fractions, with the dpm in steps (2) and (3) moving only with the fluorocitrate-containing fractions. In addition, capillary GC (30 m DB-5) was used to quantify citrate, isocitrate and fluorocitrate trimethyl esters and benzoates in each fraction. Finally, dpm were observed only in the erythro isomer of trimethyl 2-fluorocitrate benzoate. The progress of the purification is given in Table 2. Full details will be published separately(25). 

Source Adapted from Kurihara. " At least five different forms of thaumatin and four different forms of mabinlin have been identified. A chromatographic fraction containing a 12 kDa protein was sweet. This same fraction, when subjected to electrophoresis under nonreducing conditions showed bands in the region between 22 kDa and 41 kDa, su esting the presence of subunits. 

Preparative chromatographic fractionation of NA yielded kaemferol 3-glucuronide (K-3-G), previously described in esula (16), and acid (11) as major constituents. Lettuce seed... 

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