scholarly journals Rapid optimization of immunoadsorbent characteristics

1984 ◽  
Vol 221 (1) ◽  
pp. 113-120 ◽  
Author(s):  
J Janatova ◽  
R J Gobel

Immunoaffinity chromatography is employed in many research areas. We have developed an assay system that overcomes some of the tediousness and uncertainty in dealing with immunoadsorbents (IA). The preparation of IA and the effect of various procedures on the dissociation of antigen-antibody complex and the regeneration of IA are rapidly screened by polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate. Non-covalently bound proteins are dissociated and separated during the electrophoresis from IA beads. A wide variety of associative and dissociative conditions can be tested on small amounts of IA. Information about biospecifially and non-biospecifically adsorbed proteins can also be obtained. By using relatively small volumes of media containing either an antigen or another biospecific molecule, the optimal parameters for affinity chromatography (specificity, binding capacity, efficiency of solvents in dissociation of the complex and their effect on the adsorbent), or even for ion-exchange chromatography, can be determined without first performing several time- and material-consuming chromatographic experiments.

1979 ◽  
Vol 177 (2) ◽  
pp. 509-520 ◽  
Author(s):  
R Casey

The potential of immunoaffinity chromatography as a means of purifying legumin from a wide range of Pisum (pea) types was assessed. The method required small amounts of highly purified legumin from a single Pisum type, and this was obtained by salting out with (NH4)2SO4 followed by zonal isoelectric precipitation, ion-exchange chromatography on DEAE-cellulose and sucrose-density-gradient centrifugation. Some physiocochemical properties of purified legumin were determined, a number of which (Strokes radius, subunit molecular weights, subunit N-terminal residues and subunit molar ratios) have not previously been reported for Pisum legumin. Examination of Pisum legumin by two-dimensional gel isoelectric focusing/electrophoresis indicated the existence of extensive subunit heterogeneity, and polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate showed apparent variation in the nature of this heterogeneity from one Pisum variety to another. Despite this variation, immunoaffinity chromatography on immobilized anti-legumin (which was prepared by affinity chromatography on the immubolized purified legumin from the single Pisum type) was shown to be a generally applicable method for the purification of undegraded legumin from a range of pisum types, including two primate lines.


2021 ◽  
Vol 13 (2) ◽  
pp. 107-112
Author(s):  
C.F. Okechukwu ◽  
P.L. Shamsudeen ◽  
R.K. Bala ◽  
B.G. Kurfi ◽  
A.M. Abdulazeez

The most effective and acceptable therapy for snakebite victims is the immediate administration of antivenin which is limited by problems of hypersensitivity reactions in some individuals and its inability to resolve the local effects of the venom. The aim of this study was to isolate, partially purify and characterize phospholipase A2 from Naja Katiensis venom. Phospholipase A2 was partially purified via a two-step process: gel filtration on Sephadex G-75 and ion exchange chromatography using CM Sephadex, and subjected to SDS-PAGE analysis. From the results, the specific activity of the partially purified PLA2 decreased from 0.67μmol/min/mg in crude venom to 0.29μmol/min/mg after ion exchange chromatography with a yield of 5% and purification fold of 0.43. The optimum temperature of the purified PLA2 was found to be 35ºC and optimum p.H of 7. velocity studies for the determination of kinetic constants using L-a-lecithin as substrate revealed a Km  of 1.47mg/ml and Vmax  of 3.32μ moles/min/mg. The sodium dodecyl sulphate polyacrylamide gel electrophoresis of the purified PLA2 showed a distinct band with molecular weight estimated to be 14KDa. In conclusion, the present study shows that phospholipase A2 was isolated, purified and characterized. This may serve as a promising candidate for future development of a novel anti-venin drug.


1980 ◽  
Vol 192 (1) ◽  
pp. 9-18 ◽  
Author(s):  
I R Cottingham ◽  
C I Ragan

L-3-Glycerophosphate dehydrogenase (EC 1.1.99.5) was purified from pig brain mitochondria by extraction with deoxycholate, ion-exchange chromatography and (NH4)2SO4 fractionation in cholate, and preparative isoelectric focusing in Triton X-100. Sodium dodecyl sulphate/polyacrylamide gel electrophoresis shows that the purified enzyme consists of a single subunit of mol.wt. 75 000. The enzyme contains non-covalently bound FAD and low concentrations of iron and acid labile sulphide. No substrate reducible e.p.r. signals were detected. The conditions of purification, particularly the isoelectric focusing step, lead to considerable loss of FAD and possibly iron-sulphur centres. It is therefore not possible to decide with certainty whether the enzyme is a flavoprotein or a ferroflavoprotein. The enzyme catalyses the oxidation of L-3-glycerophosphate by a variety of electron acceptors, including ubiquinone analogues. A number if compounds known to inhibit ubiquinone oxidoreduction by other enzymes of the respiratory chain failed to inhibit L-3-glycerophosphate dehydrogenase, except at very high concentrations.


1978 ◽  
Vol 173 (2) ◽  
pp. 633-641 ◽  
Author(s):  
R K Craig ◽  
D McIlreavy ◽  
R L Hall

1. Guinea-pig caseins A, B and C were purified free of each other by a combination of ion-exchange chromatography and gel filtration. 2. Determination of the amino acid composition showed all three caseins to contain a high proportion of proline and glutamic acid, but no cysteine. This apart, the amino acid composition of the three caseins was markedly different, though calculated divergence values suggest that some homology may exist between caseins A and B. Molecular-weight estimates based on amino acid composition were in good agreement with those based on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. 3. N-Terminal analysis showed lysine, methionine and lysine to be the N-terminal residues of caseins A, B and C respectively. 4. Two-dimensional separation of tryptic digests revealed a distinctive pattern for each casein. 5. All caseins were shown to be phosphoproteins. The casein C preparation also contained significant amounts of sialic acid, neutral and amino sugars. 6. The results suggest that each casein represents a separate gene product, and that the low-molecular-weight proteins are not the result of a post-translational cleavage of the largest. All were distinctly different from the whey protein alpha-lactalbumin.


1997 ◽  
Vol 9 (4) ◽  
pp. 475 ◽  
Author(s):  
James R. McFarlane ◽  
Carl D. Rudd ◽  
Lynda M. Foulds ◽  
Terry P. Fletcher ◽  
Marilyn B. Renfree

Tammar wallaby (Macropus eugenii) luteinizing hormone (LH) was purified from pituitaries collected from wild and captive populations by salt sequential precipitation, ion exchange chromatography and gel filtration. Pituitary tissue (5 g) yielded 1·8 mg of purified wallaby luteinizing hormone (ME-14B), as verified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). A heterologous radioimmunoassay has been developed for measurement of LH in plasma of marsupials using a monoclonal antibody raised against bovine LH (518B7). This assay system was able to measure basal LH concentrations in male and female tammars and detected a significant rise in plasma LH in response to oestradiol benzoate in female tammars and luteinizing hormone-releasing hormone (LHRH) in males. Parallel dose–response curves were also obtained from pituitary extracts from four other species of marsupial (brushtail possum, Trichosurus vulpecula; brown antechinus,Antechinus stuartii; kowari, Dasyuroides byrnei; and Eastern pygmy possum,Cercartetus nanus) in this assay, which suggests its usefulness in the measurement of LH in other marsupial species.


1994 ◽  
Vol 266 (1) ◽  
pp. G106-G112 ◽  
Author(s):  
C. K. Chen ◽  
T. J. McDonald ◽  
E. E. Daniel

We used 125I-galanin (porcine) as ligand to study the galanin receptors in circular muscle and deep muscular plexus from canine small intestine. Specific binding sites were found in both nerve and muscle membranes. On synaptosomal membranes, the equilibrium binding study showed a high-affinity (dissociation constant, Kd = 1.1 +/- 0.13 nM; maximum binding capacity, Bmax = 244 +/- 2.1 fmol/mg) binding site. The specific binding of 125I-galanin to nerve membrane was inhibited by galanin or NH2-terminal galanin fragments but not by the COOH-terminal fragment. Computer analysis suggested a two-site model (inhibitor constants, Ki1 = 0.02 +/- 0.005 nM and Ki2 = 1.05 +/- 0.3 nM) for competition by galanin-(1-29). Kinetic and competition studies using guanosine 5'-O-(3-thiotriphosphate) or pertussis toxin (PTX) suggested that the high-affinity binding site involved a PTX-sensitive G protein which acted to slow dissociation of bound galanin from the receptor. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the galanin receptor complex revealed a radioactive band at 50 kDa. We conclude that, in canine small intestine, galanin may act as an inhibitory neuromodulator by a PTX-sensitive G protein-coupled interaction of galanin and its specific receptor on enteric nerve synaptosomes


Blood ◽  
1993 ◽  
Vol 82 (11) ◽  
pp. 3343-3349 ◽  
Author(s):  
PC Simons ◽  
L Elias

Abstract This laboratory has been characterizing protein serine/threonine kinase reactions of hematopoietic tissues, whose most distinguishing characteristics in vitro are stimulation with vesicular phosphatidyl glycerol, and the ability to function using Mn2+ as the sole divalent cation. The major protein substrates are a 73-kD protein and a protein migrating near ovalbumin on sodium dodecyl sulfate polyacrylamide gel electrophoresis. The 47-kD protein was partially purified from cells harvested by leukapheresis from a patient with acute myelogenous leukemia, using ammonium sulfate precipitation and ion exchange chromatography. This partially purified ion-exchange fraction contained an endogenous kinase activity with characteristics similar to those we previously described of protein kinase P (protein kinase, phospholipid- stimulable: PK-P), but not typical of any form of protein kinase C (PK- C). With longer phosphorylation, the 47-kD band showed increasingly lower mobility demonstrable both by Coomassie blue staining and autoradiography, suggesting both that it was multiply phosphorylated, and that the excisable band was pure. The protein was thus eluted from preparative gel slices and digested with endoproteinase lys C. Sequence data from the fragments identified the protein as the 47-kD calpain fragment of talin, a protein found in focal adhesion plaques and some cell-cell contacts. PK-C phosphorylated the 47-kD protein, as has been reported previously, and phosphopeptide mapping disclosed a similar pattern of phosphorylation using either PK-C or the endogenous activity. The 47-kD protein labeled with the endogenous kinase contained predominantly phosphoserine, with some phosphothreonine and a trace of phosphotyrosine. Intact, purified talin was also phosphorylated by PK-P in a phospholipid-stimulable manner, but at 1/20 the rate of the 47-kD fragment.


2004 ◽  
Vol 70 (4) ◽  
pp. 2367-2372 ◽  
Author(s):  
Xiaokun Wang ◽  
Xin Geng ◽  
Yukari Egashira ◽  
Hiroo Sanada

ABSTRACT Dietary ferulic acid (FA), a significant antioxidant substance, is currently the subject of extensive research. FA in cereals exists mainly as feruloylated sugar ester. To release FA from food matrices, it is necessary to cleave ester cross-linking by feruloyl esterase (FAE) (hydroxycinnamoyl esterase; EC 3.1.1.73). In the present study, the FAE from a human typical intestinal bacterium, Lactobacillus acidophilus, was isolated, purified, and characterized for the first time. The enzyme was purified in successive steps including hydrophobic interaction chromatography and anion-exchange chromatography. The purified FAE appeared as a single band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with an apparent molecular mass of 36 kDa. It has optimum pH and temperature characteristics (5.6 and 37°C, respectively). The metal ions Cu2+ and Fe3+ (at a concentration of 5 mmol liter−1) inhibited FAE activity by 97.25 and 94.80%, respectively. Under optimum pH and temperature with 5-O-feruloyl-l-arabinofuranose (FAA) as a substrate, the enzyme exhibited a K m of 0.0953 mmol liter−1 and a V max of 86.27 mmol liter−1 min−1 mg−1 of protein. Furthermore, the N-terminal amino acid sequence of the purified FAE was found to be A R V E K P R K V I L V G D G A V G S T. The FAE released FA from O-(5-O-feruloyl-α-l-arabinofuranosyl)-(1→3)-O-β-d-xylopyranosyl-(1→4)-d-xylopyranose (FAXX) and FAA obtained from refined corn bran. Moreover, it released two times more FA from FAXX in the presence of added xylanase.


2000 ◽  
Vol 44 (11) ◽  
pp. 3003-3007 ◽  
Author(s):  
Nicola Franceschini ◽  
Berardo Caravelli ◽  
Jean-Denis Docquier ◽  
Moreno Galleni ◽  
Jean-Marie Frère ◽  
...  

ABSTRACT VIM-1 is a new group 3 metallo-β-lactamase recently detected in carbapenem-resistant nosocomial isolates of Pseudomonas aeruginosa from the Mediterranean area. In this work, VIM-1 was purified from an Escherichia coli strain carrying the cloned bla VIM-1 gene by means of an anion-exchange chromatography step followed by a gel permeation chromatography step. The purified enzyme exhibited a molecular mass of 26 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and an acidic pI of 5.1 in analytical isoelectric focusing. Amino-terminal sequencing showed that mature VIM-1 results from the removal of a 26-amino-acid signal peptide from the precursor. VIM-1 hydrolyzes a broad array of β-lactam compounds, including penicillins, narrow- to expanded-spectrum cephalosporins, carbapenems, and mechanism-based serine-β-lactamase inactivators. Only monobactams escape hydrolysis. The highest catalytic constant/Km ratios (>106M−1 · s−1) were observed with carbenicillin, azlocillin, some cephalosporins (cephaloridine, cephalothin, cefuroxime, cefepime, and cefpirome), imipenem, and biapenem. Kinetic parameters showed remarkable variability with different β-lactams and also within the various penam, cephem, and carbapenem compounds, resulting in no clear preference of the enzyme for any of these β-lactam subfamilies. Significant differences were observed with some substrates between the kinetic parameters of VIM-1 and those of other metallo-β-lactamases. Inactivation assays carried out with various chelating agents (EDTA, 1,10-o-phenanthroline, and pyridine-2,6-dicarboxylic acid) indicated that formation of a ternary enzyme-metal-chelator complex precedes metal removal from the zinc center of the protein and revealed notable differences in the inactivation parameters of VIM-1 with different agents.


1973 ◽  
Vol 135 (4) ◽  
pp. 705-711 ◽  
Author(s):  
Aftab A. Ansari ◽  
A. Salahuddin

Unlike previous reports that the ovalbumin–anti-ovalbumin complex did not dissociate completely in acid media, our results showed complete dissociation of the complex both in 1.2m-acetic acid, pH2.3, and in KCl–HCl, pH2.2, I 0.06. Thus Sephadex chromatography of the solution obtained by dissolving the antigen–antibody precipitate in these media repeatedly gave two peaks corresponding to anti-ovalbumin and ovalbumin. Further, gel-diffusion and immunoelectrophoresis experiments showed that the phosphate groups of ovalbumin are not involved in the antigenic sites. The antibody thus purified was more easily precipitated than previous preparations. The molecular weight and Stokes radius of the antibody were calculated from its gel-filtration behaviour and were found to be 148000 and 4.8nm respectively. The molecular weight determined by sodium dodecyl sulphate–polyacrylamide gel electrophoresis was essentially similar (about 0.7% lower).


Sign in / Sign up

Export Citation Format

Share Document