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Heparin-agarose chromatography for the purification of tetrahydrofolate utilizing enzymes: C1-tetrahydrofolate synthase and 10-formyltetrahydrofolate synthetase.

Rapid and convenient purification procedures based upon heparin-agarose chromatography for C1-tetrahydrofolate synthase from Saccharomyces cerevisiae and 10-formyltetrahydrofolate synthetase from Clostridium acidi-urici have been developed. The purification of the yeast enzyme involves three chromatographic steps that can be done rapidly, with no intervening dialyses, and results in high yield. The first step alone, heparin-agarose chromatography, is sufficient to purify the enzyme from yeast bearing a cloned copy of the ADE3 gene that overexpresses the protein. The other steps in the purification from wild-type yeast are matrex gel red A and phenyl-Sepharose chromatography. The purification of the clostridial enzyme involves protamine sulfate fractionation and heparin-agarose chromatography. Heparin-agarose also binds two other enzymes that use tetrahydrofolate, 5,10-methenyltetrahydrofolate cyclohydrolase and 5,10-methylenetetrahydrofolate dehydrogenase. Thus, heparin-agarose should prove useful in purification of a variety of enzymes that utilize tetrahydrofolate or its derivatives as a cofactor.

Aminohydrolases↗

Separation of human IgA1 and IgA2 using jacalin-agarose chromatography.

A lectin isolated from the tropical jackfruit, jacalin, previously reported to precipitate human immunoglobulin A (IgA), and conjugated to agarose was used to separate the two subclasses of IgA from secretions. Jacalin-agarose binds specifically to the D-galactose moiety of IgA1 but not to IgA2 which has a different carbohydrate content and structure. IgA2 passed through the jacalin-agarose column and was collected in the void volume. IgA1 was eluted from the lectin by 0.8 M galactose. Of a representative diluted anti-alpha chain-purified colostral IgA preparation containing 50.2 micrograms IgA1 and 55.8 micrograms IgA2, 40.3 micrograms IgA1 (80.3% of the original) and 49.6 micrograms IgA2 (88.9%) was collected following jacalin-agarose chromatography. The jacalin-purified IgA1 fraction contained 8.0% IgA2 and the IgA2 fraction contained no IgA1. In addition, the IgA1 and IgA2 fractions had naturally occurring antibody activity to a normal oral bacterium. The method is easy, reproducible and specific and has many applications to mucosal immunological investigations.

Chromatography, Agarose↗

Isolation and characterization of linear polylactosamines containing one and two site-specifically positioned Lewis x determinants: WGA agarose chromatography in fractionation of mixtures generated by random, partial enzymatic alpha3-fucosylation of pure polylactosamines.

We report that isomeric monofucosylhexasaccharides, Galbeta1-4GlcNAcbeta1-3Galbeta1-4GlcNAcbeta1- 3Galbeta1-4(Fucalpha1-3) GlcNAc, Galbeta1-4GlcNAcbeta1-3Galbeta1-4(Fucalpha1-3) GlcNAcbeta1-3Galbeta1-4 GlcNAc and Galbeta1-4(Fucalpha1-3)GlcNAcbeta1-3Galbeta1- 4GlcNAcbeta1-3Galbeta1-4 GlcNAc, and bifucosylhexasaccharides Galbeta1-4GlcNAcbeta1-3Galbeta1-4(Fucalpha1-3) GlcNAcbeta1-3Galbeta1-4(Fucalpha1-3)GlcNAc, Galbeta1-4(Fucalpha1-3)GlcNAcbeta1-3Galbeta1- 4GlcNAcbeta1-3Galbeta1-4 (Fucalpha1-3)GlcNAc and Galbeta1-4(Fucalpha1-3)GlcNAcbeta1-3Galbeta1-4( Fucalpha1-3)GlcNAcbeta1-3Galbeta1-4GlcNAc can be isolated in pure form from reaction mixtures of the linear hexasaccharide Galbeta1-4GlcNAcbeta1-3Galbeta1-4GlcNAcbeta1- 3Galbeta1-4GlcNAc with GDP-fucose and alpha1,3-fucosyltransferases of human milk. The pure isomers were characterized in several ways;1H-NMR spectroscopy, for instance, revealed distinct resonances associated with the Lewis x group [Galbeta1-4(Fucalpha1-3)GlcNAc] located at the proximal, middle, and distal positions of the polylactosamine chain. Chromatography on immobilized wheat germ agglutinin was crucial in the separation process used; the isomers carrying the fucose at the reducing end GlcNAc possessed particularly low affinities for the lectin. Isomeric monofucosyl derivatives of the pentasaccharides GlcNAcbeta1-3Galbeta1-4GlcNAcbeta1-3Galbeta1- 4Gl cNAc and Galalpha1-3Galbeta1-4GlcNAcbeta1-3Galbeta1-4G lcN Ac and the tetrasaccharide Galbeta1-4GlcNAcbeta1-3Galbeta1-4GlcNAc were also obtained in pure form, implying that the methods used are widely applicable. The isomeric Lewis x glycans proved to be recognized in highly variable binding modes by polylactosamine-metabolizing enzymes, e.g., the midchain beta1,6-GlcNAc transferase (Leppänen et al., Biochemistry, 36, 13729-13735, 1997).

Amino Sugars↗

Selective purification of supercoiled plasmid DNA from clarified cell lysates with a single histidine-agarose chromatography step.

The ability to isolate sc (supercoiled) pDNA (plasmid DNA) isoform should be one of the features of a pDNA purification process, eliminating sample contaminants such as RNA, gDNA (genomic DNA), proteins and endotoxins. A process is described that uses a single histidine-agarose chromatography step to purify sc pDNA from other isoforms and Escherichia coli impurities present in a clarified lysate. The histidine-agarose support combines the mild hydrophobic characteristics of an epoxy spacer arm with a pseudo-affinity histidine ligand. The 6 kb DNA vaccine backbone pVAX1-LacZ was used as a model target. Following loading at high salt [2.3 M (NH4)2SO4], the different species were eluted by a series of reverse salt step gradients (2.0, 1.5 and 0 M (NH4)2SO4). Open circular pDNA and gDNA was eluted at 2.3 M, sc pDNA was isolated as a single peak at 2.0 M and RNA was eluted at 1.5 M (NH4)2SO4 and lower. The underlying mechanism is thought to involve not only hydrophobic interactions between the support and pDNA molecules, but also non-specific biorecognition of nucleic acid bases by the histidine ligand. Control analysis showed that the isolated sc pDNA conforms to specifications in terms of gDNA (3.4 ng/microg of pDNA), endotoxins (0.02 endotoxin unit/microg of pDNA), RNA and proteins (undetectable) and pDNA homogeneity (approximately 100% sc). Furthermore, the transfection efficiency of Chinese-hamster ovary cells (50%) was significantly higher when compared with the efficiency (25%) of a pDNA control. The present study confirms the possibility of using a single histidine-agarose chromatography step to purify sc pDNA from other isoforms and host contaminants present in a clarified E. coli lysate.

Chromatography, Affinity↗

Free gp70 from FeLV: enrichment from cell culture fluid by ferric oxide-agarose chromatography.

A new chromatographic material based on beads of macroporous crosslinked agarose containing ferric oxide particles was used for enrichment of gp70--the envelope glycoprotein of feline leukemia virus (FeLV). Free gp70 was purified from cell culture fluid in one step with a recovery of 50 to 60% and a purification of about 60 times. The described procedure is a suitable first step for the purification of gp70 from large volumes of cell culture fluid.

Animals↗

RNA aggregation during sulfhydryl-agarose chromatography of mercurated RNA.

Isolation of newly synthesized mercurated RNA transcripts by chromatography on sulfhydryl-agarose has recently been used to reduce contamination by endogenous RNA derived from the chromatin template. We show that substantial RNA aggregation occurs during standard isolation procedures, causing significant retention of endogenous (unmercurated) RNA on sulfhydryl-agarose. We describe methods to reduce substantially this problem and discuss the implications of our findings for interpretation of previous hybridization and transcription experiments.

Animals↗

Purification of rat pineal hydroxyindole-O-methyltransferase using S-adenosyl-L-homocysteine agarose chromatography.

Rat pineal hydroxyindole-O-methyltransferase (HIOMT; EC 2.1.1.4) was purified by affinity chromatography using an S-adenosyl-L-homocysteine agarose column. This single-step procedure, which is rapid, simple, and applicable to small quantities of tissue, gave a large enrichment of a protein (Mr approximately 38,000) identified by SDS-PAGE and silver staining. The amino acid composition of rat HIOMT was generally similar to that of the bovine enzyme, although some differences were apparent. This method will be valuable in isolating sufficient rat HIOMT to enable its primary amino acid sequence to be determined.

Acetylserotonin O-Methyltransferase↗

Copurification of selected glycolytic enzymes with retinal S-antigen (arrestin) by hydroxyapatite agarose chromatography of bovine retina.

PURPOSE: A variety of methods have been developed for the purification of S-antigen but a simple and rapid procedure based on hydroxyapatite-agarose (HA) adsorbtion is most widely used. In the present study, we investigated the nature of proteins purified with the aid of HA chromatography. METHODS: After elimination of retinal S-antigen by HA, the soluble extract of retinal tissue was readsorbed on HA. The proteins were thereafter desorbed by 10 to 500 mM phosphate buffer gradient. Two peaks obtained by SDS-PAGE were used for the generation of specific antisera for subsequent analysis by ELISA and Western blotting. RESULTS: Four proteins (two 48 kDa , one 50 kDa and one 46 kDa) were obtained in this manner. Partial amino acid sequencing permitted the identification of these proteins as alpha-enolase (48 kDa), gamma-enolase (48 kDa), Glucose-6-phosphate-Isomerase (50 kDa) and aspartate-amino-transferase (46 kDa). CONCLUSION: The selected glycolytic enzymes co-purified with retinal S-antigen by hydroxyapatite agarose chromatography of bovine retina.

Amino Acid Sequence↗

On the heterogeneity of serum albumin: effect of sodium dodecyl sulphate on agarose chromatography of the protein.

The chromatographic behaviour of serum albumin changes if it is dissolved in an aqueous solution of sodium dodecyl sulphate (SDS) and is left at room temperature or is heated. Instead of emerging as one peak from an agarose column it emerges as more than one peak and the protein in each when rechromatographed elutes in more than one peak. Electropherograms made in the presence of SDS of the protein in these peaks show multiple banding from proteins migrating with a wide range of molecular weights. The chromatographic and electrophoretic behaviour of serum albumin in the presence of SDS suggests that the protein is not a simple monomer and alternative explanations for this behaviour are discussed.

Animals↗

Specific isolation by anhydrotrypsin-agarose chromatography of a recombinant protein tagged with an affinity tail arginine at the C-terminus.

A characteristic property of anhydrotrypsin, i.e., its ability to strongly bind C-terminal arginine, proved to be useful as a tool for specific enrichment of a recombinant protein. An arginine tail was introduced at the C-terminus, for example, of a human beta-galactoside-binding lectin by site-directed mutagenesis. The resulting mutant recombinant lectin, which retained sugar-binding activity as high as the wild-type lectin, became recognizable by anhydrotrypsin. It was adsorbed on an anhydrotrypsin-agarose column and eluted with benzoylglycylarginine. The added arginine tail could be specifically removed by carboxypeptidase B. When E. coli lyzate containing the mutant lectin was applied to the column more than 10-fold enrichment of the mutant lectin was attained. This procedure should be generally applicable and may be advantageous because the addition of a single arginine residue may have minimal effect on the structure and function of the target protein.

Arginine↗

alpha 1,3-Fucosylation of branched blood group I-type oligo-(N-acetyllactosamino)glycans by human milk transferases is restricted to distal N-acetyllactosamine units: the resulting isomers are separated by WGA-agarose chromatography.

A partially purified preparation of alpha 1,3-fucosyltransferase(s) from human milk was used to [14C]fucosylate oligosaccharides containing Gal beta 1-4GlcNAc units. Substitution of N-acetyllactosamine at position 3' with a beta-linked N-acetyl-glucosamine enhanced the reactivity of the acceptor, whereas similar substitution at position 6' was inhibitory. Thus, the trisaccharide GlcNAc beta 1-6Gal beta 1-4GlcNAc (5), the branched tetrasaccharide GlcNAc beta 1-3(GlcNAc beta 1-6)Gal beta 1-4GlcNAc (11) and the triply branched decasaccharide GlcNAc beta 1-3(GlcNAc beta 1-6)Gal beta 1-4GlcNAc beta 1-3[GlcNAc beta 1-3(GlcNAc beta 1-6)Gal beta 1-4GlcNAc beta 1-6]Gal beta 1-4GlcNAc (26) gave remarkably poor yields of alpha 1,3-fucosylated products in comparison to GlcNAc beta 1-3Gal beta 1-4GlcNAc (3). beta 1,4-Galactosyl derivatives of 5 and 11, however, gave good yields of alpha 1,3-fucosylated products, but the fucosylation was restricted to the distal N-acetyllactosamine units of Gal beta 1-4GlcNAc beta 1-6Gal beta 1-4GlcNAc (16), Gal beta 1-4GlcNAc beta 1-3(Gal beta 1-4GlcNAc beta 1-6)Gal beta 1-4GlcNAc (18) and also in Gal alpha 1-3Gal beta 1-4GlcNAc beta 1-3(Gal alpha 1-3Gal beta 1-4GlcNAc beta 1-6)Gal beta 1-4GlcNAc (22). Immobilized wheat germ agglutinin (WGA), possessing high affinity for 16 [1], revealed no affinity for the fucosylated derivative Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-6Gal beta 1-4GlcNAc (17). The isomeric heptasaccharides Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3(Gal beta 1-4GlcNAc beta 1-6)Gal beta 1-4GlcNAc (19) and Gal beta 1-4GlcNAc beta 1-3[Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-6]Gal beta 1-4GlcNAc (20) were readily separated from each other on WGA agarose, and so were the isomeric nonasaccharides Gal alpha 1-3Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3(Gal alpha 1-3Gal beta 1-4GlcNAc beta 1-6)Gal beta 1-4GlcNAc (23) and Gal alpha 1-3Gal beta 1-4GlcNAc beta 1-3[Gal alpha 1-3Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-6]Gal beta 1-4GlcNAc (24).

Agglutinins↗

Characterization of a rat liver cyclic GMP-activated phosphodiesterase by chromatography on hexyl-agarose. Inhibition of phosphodiesterase activity by hexyl-agarose.

Chromatography on hexyl-agarose resolved a partially purified cyclic GMP-activated phosphodiesterase from rat liver into two peaks of activity: the first was eluted with 0.5 M-KCl and was cyclic AMP-specific. The second was tightly bound to hexyl-agarose and was not eluted with KCl (0--2.0 M), which enhanced the hydrophobic interactions of this form with the matrix. It was eluted with 0.5 M-Tris, hydrolysed cyclic AMP and cyclic GMP and was specifically activated by cyclic GMP. The cyclic GMP-activated phosphodiesterase was immobilized on hexyl-agarose. Enzyme activity, quantitatively bound to hexyl-agarose, was not released from the hydrophobic matrix in the presence of cyclic AMP or cyclic GMP, under our assay conditions. The immobilized form of the enzyme retained catalytic activity, was inhibited by 0.1 mM-cyclic AMP and was activated by micromolar concentrations of cyclic GMP to a lesser extent (7-fold) than the control, i.e. the enzyme mixed with unsubstituted agarose (15-fold). When the enzyme was immobilized, inhibition of cyclic AMP phosphodiesterase activity was only observed in the presence of cyclic GMP (at 3 microM); in its absence, activity remained unchanged. The kinetic behaviour of the immobilized enzyme is consistent with the hypothesis of a binding site distinct from the hydrolytic and activating sites.

3',5'-Cyclic-GMP Phosphodiesterases↗