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Simple Purification (simple + purification)

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Chemistry60%

Selected Abstracts

Simple Purification of Immunoglobulins from Whey Proteins Concentrate

BIOTECHNOLOGY PROGRESS, Issue 2 2006
Benevides C. C. Pessela
We have developed a new protocol with only two steps for purification of immunoglobulins (Ig) from a protein concentrate of whey. Following this protocol, we have an 80% recovery of immunoglobulins, fairly pure. The purification was achieved by eliminating the BSA, via a strong adsorption on DEAE-agarose. Full desoprtion of the other serum proteins could be achieved without contamination with BSA. Thus, a protein solution containing only Ig and very small proteins (e.g., ,-lactoglobulins and ,-lactalbumin) was obtained. Offering this protein mixture to a lowly activated aminated support, only Ig adsorbed on the support. It has been shown that BSA is able to interact with other proteins (including Ig and lactalbumins). This ability to form complexes with other proteins prevented the success of the direct adsorption of Ig on this mildly activated support, even although Ig should be the largest protein presented in dairy whey. [source]

Site-specific synthesis of Amadori-modified peptides on solid phase

JOURNAL OF PEPTIDE SCIENCE, Issue 6 2006
Andrej Frolov
Abstract Glycation of peptides and proteins is a slow chemical reaction of reducing sugars modifying the amino groups. The first intermediates of this nonenzymatic glycosylation are the Amadori products that can undergo further chemical reactions, finally leading to advanced glycation end products (AGEs). The formation of AGEs was not only linked to aging of tissues and organs in general but also to several diseases such as diabetes mellitus and Alzheimer's disease. Because of the importance of these modifications and their potential use as diagnostic markers, a global postsynthetic approach on solid phase was developed. The peptides were synthesized by Fmoc/tBu-chemistry, with the lysine residue to be modified being protected with the very acid-labile methyltrityl group. Incubation of the peptides with D -glucose in DMF at elevated temperatures resulted in product yields of 35%. Neighboring residues with bulky protecting groups reduced the yields only slightly. The major by-products were the unmodified peptide and an oxidation product. Whereas the unmodified peptide eluted before the glycated peptide, all other by-products eluted later in RP-HPLC, allowing simple purification. Copyright © 2005 European Peptide Society and John Wiley & Sons, Ltd. [source]

Reverse ATRP process of acrylonitrile in the presence of ionic liquids

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 8 2008
Chen Hou
Abstract An ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim] [BF4]), was first used as the solvent in azobisisobutyronitrile (AIBN)-initiated reverse atom transfer radical polymerization (RATRP) of acrylonitrile with FeCl3/succinic acid (SA) as the catalyst system. The polymerization in [C4mim][BF4] proceeded in a well-controlled manner as evidenced by kinetic studies. Compared with the polymerization in bulk, the polymerization in [C4mim][BF4] not only showed the best control of molecular weight and its distribution but also provided rather rapid reaction rate with the ratio of [C4mim][BF4] at 200:1:2:4. The polymerization apparent activation energies in [C4mim][BF4] and bulk were calculated to be 48.2 and 55.7 kJ mol,1, respectively. Polyacrylonitrile obtained was successfully used as a macroinitiator to proceed the chain extension polymerization in [C4mim][BF4] via a conventional ATRP process. [C4mim][BF4] and the catalyst system could be easily recycled and reused after simple purification and had no effect on the living nature of polymerization. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2701,2707, 2008 [source]

Genotyping single nucleotide polymorphisms using intact polymerase chain reaction products by electrospray quadrupole mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 18 2001
James J. Walters
Both single nucleotide polymorphisms (SNPs) and mutations are commonly observed in the gene encoding the tumor suppressor protein, p53. SNPs occur at specific locations within genes whereas mutations may be distributed across large regions of genes. When determining nucleotide differences, mass spectrometry is the only method other than Sanger sequencing which offers direct structural information. Electrospray ionization (ESI) quadrupole mass spectrometry (MS) analysis of intact polymerase chain reaction (PCR) products was performed following a simple purification and on-line heating to limit ion adduction. The PCR products were amplified directly from genomic DNA rather than plasmids, as in our previous work. Two known polymorphisms of the p53 gene were genotyped. A cytosine (C) or guanine (G) transversion, designated C,,,G (G,,,C on the opposite strand), were each detected by a 40.0,Da change upon ESI quadrupole MS analysis. Using known PCR products as standards, the genotypes determined for 10 human samples corresponded with restriction fragment length polymorphism (RFLP) analysis. Cytosine/thymine (T) transitions, designated C,,,T (G,,,A on the opposite strand), were also genotyped by ESI-MS. This SNP is discriminated by a 15.0,Da change on one strand (C,,,T) and a 16.0,Da change on the other (G,,,A). Appropriate sample preparation and instrumental configuration (including heated sample inlet syringe and MS source), to limit adducts, are both vital for successful ESI quadrupole MS analysis of intact PCR products. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Donor-Bound Glycosylation for Various Glycosyl Acceptors: Bidirectional Solid-Phase Semisynthesis of Vancomycin and Its Derivatives

CHEMISTRY - AN ASIAN JOURNAL, Issue 1 2007
Takayuki Doi Prof.
Abstract The glycosidation of a polymer-supported glycosyl donor, N -phenyltrifluoroacetimidate, with various glycosyl acceptors is reported. The application of the polymer-supported N -phenyltrifluoroacetimidate is demonstrated in the synthesis of vancomycin derivatives. 2- O -[2-(azidomethyl)benzoyl]glycosyl imidate was attached to a polymer support at the 6-position by a phenylsulfonate linked with a C13 alkyl spacer. Solid-phase glycosidation with a vancomycin aglycon, selective deprotection of the 2-(azidomethyl)benzoyl group, and glycosylation of the resulting 2-hydroxy group with a vancosamine unit were performed. Nucleophilic cleavage from the polymer support with acetate, chloride, azido, and thioacetate ions provided vancomycin derivatives in pure form after simple purification. The semisynthesis of vancomycin was achieved by deprotection of the acetate derivative. [source]