Purification, chromatographic

Once the protein is recovered from its producer source and concentrated it must be purified to homogeneity. In other words, all contaminant proteins and other potential contaminants of potential medical significance (discussed in Chapter 7) must be removed. Purification is generally achieved by column chromatography. 

As with most aspects of downstream processing, the operation of chromatographic systems is highly automated and is usually computer controlled. Whereas medium-sized process-scale chromatographic columns (e.g. 5-151 capacity) are manufactured from toughened glass or plastic, larger 

Irrigate with buffer (wash out unbound material) 

Ion-exchange chromatography Gel-filtration chromatography Affinity chromatography 

Differences in protein surface charge at a given pH Differences in mass/shape of different proteins Based upon biospecific interaction between a protein and an appropriate ligand 

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Bis(3,4-diethyl-2-pyrrolylmethyl)-3,4-dietliyl-l//-pyrrole (2), prepared in situ from the di-t-butylester of the 5,5 -dicarboxylic acid (/), reacts with 4//-1,2,4-triazole-3,5-dialdehyde (3) in di-chloromethane in the presence of trifluoroacetic acid and 2,3-dichloro-5,6-dicyano-/)-benzoquino-ne as an oxidation reagent. Dark blue crystals are obtained after chromatographic purification. The dark violet chloroform solution fluoresces purple at 360 nm and gives the NMR experiments 39. Which compound and which tautomer of it has been formed ... 

The lipophilicity of this phosphate protective group helps in the chromatographic purification of oligonucleotides. It is removed by the oximate method. ... 

The reaction of l-morpholylbut-l-en-3-yne with aromatic azides gives 1-aryl-4-ethynyl-5-iV-morpholino-A -triazolines (164), which readily eliminate morpholine to form l-aryl-4-ethynyltriazole (165) during chromatographic purification (83DIS). 

Nucleoside analog 56 treated with sodium methoxide yielded a mixture, which after acetylation and chromatographic purification provided 27% of triacetate of the starting compound and 32% of diacetate 57 (Eq. 9) (78JOC4784). 

A mixture of 5 g of the 21-acetate of SCt-chlorohydrocortisone, 7 g of chloranii and 100 cc of n-amyl alcohol was refluxed for 16 hours, cooled and diluted with ether. The solution was successively washed with water, 5% sodium carbonate solution and water, dried over anhydrous sodium sulfate, filtered and evaporated to dryness under reduced pressure. Chromatographic purification of the residue yielded the 21-acetate of 6-chloro-A -pregnatriene-11 3,17a,21 -triol-3,20-dione. ... 

Jacobsen has utilized [(salen)Co]-catalyzed kinetic resolutions of tenninal epoxides to prepare N-nosyl aziridines with high levels of enantioselectivity [72], A range of racemic aryl and aliphatic epoxides are thus converted into aziridines in a four-step process, by sequential treatment with water (0.55 equivalents), Ns-NH-BOC, TFA, Ms20, and carbonate (Scheme 4.49). Despite the apparently lengthy procedure, overall yields of the product aziridines are excellent and only one chromatographic purification is required in the entire sequence. 

A mixture of 2.0 mmol of a 1.6 N solution of butyllithium in hexane and 0.47 g (2.0 mmol) of(-)-spartcinc in 10 mL of diethyl ether is stirred for 15 min at — 78 rC then 0.26 g (2.0 mmol) of 1-methyl-l//-indene in 2 mL of diethyl ether are added. Stirring is continued for 30 inin at 20 °C, the mixture is cooled to — 70 CC and 2.5 mmol of the acid chloride in 2 mL of diethyl ether are added. After stirring for 4h the usual aqueous workup was accomplished by addition of 10 mL of diethyl ether and successive washing with 10 mL of 2 N aq HC1. water and sat. aq NtiCl, respectively, followed by chromatographic purification on silica gel with diethyl cthcr/pentane. 

The related serine derived (4S)-4-methoxycarbonyl-3-(l-oxopropyl)-2-thiono-l,3-oxazolidine 11, and the cysteine derived (4A)-4-methoxycarbonyl-3-(l-oxobntyl)-2-thiono-1,3-thiazolidine 13, also serve as efficient chiral auxiliaries in boron- and tin(II)-mediated aldol condensations98. Thus, conversion of 11 into the boron or tin enolate, followed by reaction with 2-methylpropanal affords predominantly one adduct. Subsequent methanolysis and chromatographic purification delivers the syu-methyl ester in 98% ee. 

A solution of 1 equivalent of the oxazolidinone in diethyl ether is cooled to —78 C. To the resultant suspension are added 1.4 equivalents of triethylamine. followed by 1.1 equivalents of dibutylboryl triflate. The cooling bath is removed and the reaction mixture is stirred at 25 °C for 1.5 h. The resultant two-phase mixture is cooled to — 78 "C with vigorous stirring. After 1 equivalent of aldehyde is added, the reaction is stirred at —78 °C Tor 0.5 h, and 0 "C for 1 to 2 h. The solution is diluted with diethyl ether, washed with 1 N aq sodium bisulfate, and concentrated. Following oxidation with 30% aq hydrogen peroxide (10 equivalents, 1 1 methanol/water, 0 C. 1 h), extractive workup and chromatographic purification, the aldol adduct is obtained with >99% diastcrcomeric purity. 

A solution of hex-l-yne (4.5 mmol) in THF (1ml) was added slowly to lithium bis(phenyldimethylsilyl)cuprate (Chapter 8) (5 mmol, based on CuCN) at 0°C, and the mixture was stirred for 15min at 0°C. Saturated ammonium chloride solution (1 ml) was added, and stirring was continued for 5 min at 0°C. Light petroleum was then added, and the organic layer was washed with ammonium chloride solution, and dried. Concentration and chromatographic purification on silica gel gave the vinylsilane (4.23 mmol, 94%). 

To a solution of the carboxylic acid (2.1 mmol) in THF (40 ml) was added, 2-trimethylsilylethanol (4.2mmol) and TMSC1 (16,5mmol). The mixture was stirred under reflux for 36 h, cooled, and concentrated in vacuo. Direct chromatographic purification gave the ester (73-98%). 

HF-induced elimination (5). To a solution of aqueous HF (4 drops, 50%) in MeCN (8 ml) was added a solution of the /3-hydroxysilane (lmmol) in MeCN (2ml), and the mixture was stirred at room temperature until t.l.c. analysis indicated completion (5-20min). The reaction mixture was then partitioned between pentane (50 ml) and saturated sodium hydrogen carbonate solution (10ml). The aqueous layer was extracted thoroughly with pentane (3 x 50 ml), and the combined organic extracts were washed with brine and dried. Concentration followed by chromatographic purification gave the product alkenes. 

The submitters purified the product by the following procedure. The residual pale yellow solid is dissolved in 50 ml of diethyl ether and the remaining solid is filtered off (Note 16). The filtrate is concentrated to a volume of ca. 25 mL, and the solution is allowed to crystallize at 0°C. Once crystallization begins, 50 mL of petroleum ether is added in two portions over 10 hr, and then crystallization is allowed to proceed overnight at 0°C. The white solid is collected by filtration and washed with a mixture of 3 1 petroleum ether-diethyl ether to afford 3.8 g of 4. Chromatographic purification of the mother liquor (5.5 x 18 cm of DSH silica gel 40-63 mm, elution with 1 L of petroleum ether/ethyl acetate 4 1 followed by 1.5 L of 3 1 petroleum ether-ethyl acetate) gives 2.5 g of 4 as a pale yellow solid. All the material is combined and recrystallized from diethyl ether/petrol as above to yield 5.2 g (47%) of 4 in two crops. 

Fibrinolytic effecting protease enzyme with glycoprotein structure relative mol mass ca. 30000. Isolation from the poison secretion (venom) of Agkistrodon rhodostoma (malayan pit viper) with chromatographic purification. 

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

Proteolytic enzyme from the latex of Carica papaya with an approximate molecular weight of 27000. It is differentiated from papain in electrophoresis behavior, in solubility and in substrate specifity. Isolation by acidify of papaya-latex with HCl, salting out with NaCl and following chromatographic purification. The formulation contains L-cysteine as reducing agent. 

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 cultures of Actinomyces antibioticus and chromatographic purification on AI2O3. Reference s) ... 

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

The Reeopet process for the ehemical recycling of PETP is described. The three-stage process, which allows the recovery of highly pure terephthalic acid, commences with continuous saponification followed by chromatographic purification with activated carbon and a final acidification step. 

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