Column chromatographic purifications

From culture of Streptomyces verticillus by ion-exchange adsorption and column chromatographic purification (on alumina) via the copper complex. 

Cyclic peptide from 11 amino acids. Preparation by fermentation of Tolypocladium inflatum Gams with addition of DL-a-aminobutyric acid to the fermentation medium. Isolation by homogenization of mycelium, extraction with 90 % methanol and column chromatographic purification. 

From culture of Streptomyces caespilosus column chromatographic purification. Reference(s) ... 

By extraction of the fruits of Silybwn inarianwn Gaertn. (milk thistle) and column chromatographic purification. 

Dialyze the oxidized liposomes against 20mM sodium borate, 0.15M NaCl, pH 8.4, to remove unreacted periodate. This buffer is ideal for the subsequent coupling reaction. Chromatographic purification using a column of Sephadex G-50 also can be done. 

Streptokinase is a 48 kDa extracellular bacterial protein produced by several strains of Streptococcus haemolyticus group C. Its ability to induce lysis of blood clots was first demonstrated in 1933. Early therapeutic preparations administered to patients often caused immunological and other complications, usually prompted by impurities present in these products. Chromatographic purification (particularly using gel filtration and ion-exchange columns) overcame many of these initial difficulties. Modern chromatographically pure streptokinase preparations are usually supplied in freeze-dried form. These preparations (still obtained by non-recombinant means) often contain albumin as an excipient. The albumin prevents flocculation of the active ingredient upon its reconstitution. 

Concentration of the crude product should be stopped when solids begin to form. The checkers observed that it was difficult to dissolve the crystalline crude product in ether to load the column for chromatographic purification. 

Chromatographic purification of cross-links. The initial steps of the purification were to separate the cross-links from monomeric amino acids, followed by the separation of individual cross-links. The acid hydrolyzate of demineralized roof powder (13.0 g collagen) was separafed on a size exclusion column fo yield the high molecular weight fractions. 

When intermediate 274 reacted with ketones 133 (from D-glucose) or 270 (from D-fructose), mixed steroid-sugar compounds 278 and 279 were, respectively, obtained in low yields (10-16%). In addition, the use of protected estrone 280 (precursor of the epoxide 272) as electrophile allows the preparation of the dimeric steroid 281 in 26% yield. The low yields obtained for compounds 278, 279 and 281 are due to extensive decomposition during their column chromatographic purification. 

Step. The clean-up was carried out mainly using an open column chromatographic purification, but more recently has been substituted by SPE cartridges, as C18 [422], C2 [423], and Chromabond XTR [426],... 

Figure 8.3. Chromatographic purification of recrystallized insulin on a Sephadex G-50 gel filtration column. Separation of high molecular mass proteolytic enzymes, as well as proinsulin and some very low molecular mass material, is obvious. Insulin elutes from the column as a single peak, hence the term single peak insulin ...

The octapeptide 27 (419 mg, 0.3 mmol) was hydrogenated over Pd/C in DMF (300 mL). The catalyst was removed by filtration, the filtrate concentrated, diluted with H20 (27mL), and extracted with Et20. The aqueous soln was passed through an ion-exchange column and the oxytocin analogue was obtained upon chromatographic purification yield 62 mg (83%) [a]D22 -98.4 (c 0.46, H20). 

Procedures. Chromatographic Purification of Ozonization Products. Ozonization products from ethyl 10-undecenoate and 1-octene were chromatographed on silica gel columns (Baker) and eluted with 15 or 25% ether in petroleum ether (b.p., 30°-60°). Fractions were examined by thin-layer chromatography (TLC) on silica gel G Chroma-gram sheet eluted with 40% ether in petroleum ether. For development of ozonide and peroxide spots, 3% KI in 1% aqueous acetic acid spray was better than iodine. The spots (of iodine) faded, but a permanent record was made by Xerox copying. Color of die spots varied from light brown (ozonide) to purple-brown (hydroperoxide), and the rate of development of this color was related to structure (diperoxide > hydroperoxide > ozonide). 2,4-Dinitrophenylhydrazine spray revealed aldehyde spots and also reacted with ozonides and hydroperoxides. Fractions were evaporated at room temperature or below in a rotary evaporator. 

Online dialysis and subsequent trace enrichment has been further described for isolation/purification of flumequine residues from fish muscle (203), or oxolinic acid and flumequine from chicken liver (193) and salmon muscle (204). This involves online purification by diphasic dialysis membrane and trapping of the analytes onto a liquid chromatographic preconcentration column (reversed-phase Ci8 or polymeric), rinsing of the coextracted materials to waste, and finally flushing of die concentrated analytes onto the analytical column. 

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