scholarly journals Immunoaffinity chromatography as a means of purifying legumin from Pisum (pea) seeds

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.

1979 ◽  
Vol 183 (3) ◽  
pp. 539-545 ◽  
Author(s):  
M Paulsson ◽  
D Heinegård

Proteoglycans were extracted from bovine tracheal cartilage by high-speed homogenization, the use of dissociative solvents being avoided. The homogenate was fractionated by gel chromatography, sucrose-density-gradient centrifugation and ion-exchange chromatography. A previously unrecognized protein, cartilage matrix protein, was identified by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. It cofractionated with the proteoglycans in all systems, indicating an interaction. The cartilage matrix protein-proteoglycan complex was dissociated by treatment with 4M-guanidinium chloride. The complex again formed when the guanidine was removed. The cartilage matrix protein has a mol.wt. of more than 200000. On reduction it yields subunits with a mol.wt. of approx. 60000.


1978 ◽  
Vol 171 (2) ◽  
pp. 445-451 ◽  
Author(s):  
K S Zänker ◽  
W Schiebel

Cytoplasmic DNA polymerase (DNA deoxynucleotidyltransferase, EC 2.7.7.7) was partially purified from Physarum polycephalum. The first step of the purification procedure utilized the fact that the enzyme on gel filtration behaves in anomalous fashion. The second step was either ion-exchange chromatography or sucrose-density-gradient centrifugation. The partially purified DNA polymerase was heterogeneous and at least four species with different sedimentation coefficients (5.5S, 7.2S, 8.6S and 11.5S) were detected. Calculated molecular weights indicated a tendency for stoicheiometric polypeptide aggregation, accompanied by an alteration of the three-dimensional structure froma compact spheroid to a more open elliptical form. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and computed molecular weights suggest an active protomer in the range of 113000 daltons; all data pertain to I 0.045, which was maintained during the whole procedure.


1983 ◽  
Vol 210 (1) ◽  
pp. 259-263 ◽  
Author(s):  
J Hubbard ◽  
M Kalimi

Citrate greatly stabilized rat hepatic unbound glucocorticoid receptors in cell-free conditions at 4 degrees C with optimal effectiveness at 5-15 mM. Control receptors were inactivated at 4 degrees C with a half-life of less than 12 h. However, in the presence of 10 mM-citrate, unbound receptors were almost completely stabilized for 48 h at 4 degrees C. Citrate at a concentration of 1-2 mM yielded half-maximal stabilization. The stabilizing effect of citrate was rather specific, as succinate, alpha-oxoglutarate, oxaloacetate, malate and pyruvate had no apparent stabilizing action. Citrate stabilized receptors over a wide range of H+ concentrations, with complete protection between pH 6.5 and 8.5. In addition, citrate appeared to have a significant effect on glucocorticoid-receptor complex activation into a nuclear binding form. Thus 5-10 mM-citrate enhanced nuclear binding, with optimal activation achieved at 10 mM concentration. As analysed by sucrose-density-gradient centrifugation and DEAE-cellulose chromatography, no apparent change was observed in the physical characteristics of the glucocorticoid receptor in the presence of citrate.


1985 ◽  
Vol 228 (1) ◽  
pp. 111-117 ◽  
Author(s):  
E Davies Jones ◽  
F A Hashim ◽  
Y Kajita ◽  
F M Creagh ◽  
P R Buckland ◽  
...  

Reduction of human thyroid membranes with dithiothreitol caused the release of a water-soluble glycoprotein which neutralized the thyrotropin (TSH) receptor-binding and thyroid-stimulating activities of Graves‘ serum. Analysis of the protein by gel filtration and sucrose density gradient centrifugation allowed estimates of 3.45 nm for the Stokes’ radius, 3.6 S for the s20,w and 47 000 +/- 5000 (mean +/- S.D.; n = 4) for the Mr. The material released by dithiothreitol treatment could be crosslinked to 125I-labelled TSH coupled to N-hydroxysuccinimidyl 4-azidobenzoate (125I-HSAB-TSH), suggesting that it contained a component of the TSH receptor. Furthermore, analysis of the crosslinked material by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis indicated that it contained the TSH receptor A subunit (Mr 50 000). Several factors suggested therefore that the glycoprotein released by dithiothreitol treatment of human thyroid membranes was the TSH receptor A subunit. In particular, (a) both preparations were hydrophilic and were released from membranes by reduction, (b) they had similar Mr values and (c) both preparations crosslinked to 125I-HSAB-TSH. Material similar to the TSH receptor A subunit was released from thyroid membranes by treatment with papain, probably as a result of cleavage of the receptor A subunit at a site close to the interchain disulphide bridge. A similar mechanism, involving thyroid proteinases, was probably involved in release of material with similar properties to the TSH receptor A subunit during freezing and thawing of human thyroid homogenates.


1981 ◽  
Vol 88 (1) ◽  
pp. 245-250 ◽  
Author(s):  
S Tsukita ◽  
H Ishikawa ◽  
M Kurokawa

Astroglial filaments approximately 10 nm in diameter were isolated from degenerated mouse optic nerves by Triton X-100 and DNase I treatments followed by sucrose density gradient centrifugation. 2-4 wk after bilateral enucleation, optic nerves contained virtually a single population of 10-nm filaments (astroglial filaments), free from neurofilaments. In negative-staining and thin-section electron microscopy, the isolated filaments were seen as nonbranching linear structures with smooth contour, and were morphologically identical to those in situ. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed the isolated filaments to be composed of two major polypeptides with molecular weights of 45,000 and 55,000, present in an approximate molar ratio of 1:1. These findings, together with the results of one-dimensional peptide mapping and solubility study, indicate that the astroglial filaments in the mouse optic nerve are primarily composed of these two polypeptides.


1981 ◽  
Vol 195 (1) ◽  
pp. 83-92 ◽  
Author(s):  
N S Beer ◽  
W T Griffiths

A procedure for the purification of the enzyme NADPH:protochlorophyllide oxidoreductase is described. This involves fractionation of sonicated oat etioplast membranes by discontinuous-sucrose-density-gradient centrifugation, which gives membranes in which the enzyme is present at a high specific activity. The enzyme is solubilized from the membranes with Triton X-100, followed by gel filtration of the extract; enzyme activity is eluted in fractions corresponding to a mol.wt of approx. 35000. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of the enzyme-containing fractions from gel filtration shows two peptides, of mol.wts. approx. 35000 and 37000.


1985 ◽  
Vol 229 (3) ◽  
pp. 611-619 ◽  
Author(s):  
R Kobayashi ◽  
J R Reeve ◽  
J H Walsh

Canine epidermal growth factor (EGF)/urogastrone was partially purified from dog urine by fractional precipitation with (NH4)2SO4, ion-exchange chromatography with DEAE-cellulose DE-52, gel filtration with Sephadex G-50, and a second DE-52 chromatography, to yield receptor-competing activity equivalent to 13 micrograms of standard mouse EGF/litre of starting urine. The purification was monitored by a competitive radioreceptor assay using fixed monolayers of A431 cells. The partially purified canine EGF/urogastrone demonstrated a growth-stimulating activity in 3T3 mouse fibroblast cells as potent as mouse EGF. Analysis by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis revealed one major peptide component with an Mr similar to that of mouse EGF, and two minor peptides of slightly higher Mr. The major peptide component was isolated after reduction and its amino acid composition was determined.


1987 ◽  
Vol 65 (10) ◽  
pp. 899-908 ◽  
Author(s):  
F. Moranelli ◽  
M. Yaguchi ◽  
G. B. Calleja ◽  
A. Nasim

The extracellular α-amylase activity of the yeast Schwanniomyces alluvius has been purified by anion-exchange chromatography on DEAE-cellulose and gel-filtration chromatography on Sephadex G-100. Sodium dodecyl sulfate – polyacrylamide gel electrophoresis (SDS–PAGE) and N-terminal amino acid analysis of the purified sample indicated that the enzyme preparation was homogeneous. The enzyme is a glycoprotein having a molecular mass of 52 kilodaltons (kDa) estimated by SDS–PAGE and 39 kDa by gel filtration on Sephadex G-100. Chromatofocusing shows that it is an acidic protein. It is resistant to trypsin but sensitive to proteinase K. Its activity is inhibited by the divalent cation chelators EDTA and EGTA and it is insensitive to sulfhydryl-blocking agents. Exogenous divalent cations are inhibitory as are high concentrations of monovalent salts. The enzyme has a pH optimum between 3.75 and 5.5 and displays maximum stability in the pH range of 4.0–7.0. Under the conditions tested, the activity is maximal between 45 and 50 °C and is very thermolabile. Analysis of its amino acid composition supports its acidic nature.


1993 ◽  
Vol 264 (5) ◽  
pp. H1528-H1534 ◽  
Author(s):  
A. Darvish ◽  
P. J. Metting

The major enzyme responsible for adenosine production during myocardial hypoxia or ischemia is 5'-nucleotidase. We purified an AMP-specific 5'-nucleotidase to homogeneity from the 150,000-g supernatant of dog heart homogenate using phosphocellulose, DEAE-cellulose, and ADP-agarose affinity chromatography. Sodium dodecyl sulfate-poly-acrylamide gel electrophoresis of the purified enzyme yielded a single protein band of 43 kDa. The molecular mass of the holoenzyme, determined by gel filtration and sucrose density-gradient centrifugation, was approximately 166 kDa, suggesting a tetrameric structure. Dog heart cytosolic 5'-nucleotidase was active at physiological pH (6.8-7.8) and demonstrated a preference for AMP over IMP as substrate. The enzyme exhibited sigmoidal saturation kinetics, with half-maximal activity at 2.6 mM AMP in the absence of ADP. ADP (0-250 microM) activated cytosolic 5'-nucleotidase by increasing maximal velocity and affinity for AMP. The enzyme was inhibited by 4 mM ATP, but 5'-nucleotidase activity increased as [ATP] was reduced. Mg2+ was required for activity, with maximal activation at approximately 3.5 mM free Mg2+. These data suggest that the regulation of AMP-specific cytosolic 5'-nucleotidase by adenine nucleotides and free Mg2+ may be important in the production of adenosine during conditions promoting ATP hydrolysis, such as myocardial hypoxia or ischemia.


1974 ◽  
Vol 77 (3) ◽  
pp. 485-497 ◽  
Author(s):  
P. A. Torjesen ◽  
T. Sand ◽  
N. Norman ◽  
O. Trygstad ◽  
I. Foss

ABSTRACT Highly purified human LH, FSH and TSH were isolated from batches of 300 frozen pituitary glands (200 g) by pH, acetone and ethanol fractionation, Sephadex gel filtration, ion-exchange chromatography on DEAE-cellulose and CM-Sephadex, and preparative polyacrylamide-gel electrophoresis. Sodium dodecyl-sulphate (SDS) polyacrylamide gel electrophoresis was used in order to check the purity, the identity and the molecular weight of the purified LH, FSH and TSH. This procedure showed that the hormone preparations consisted of two subunits with molecular weights of: LH: 21 300 and 17 900, FSH: 22 100 and 18 300 and TSH: 20 800 and 16 400. The purity of the hormone preparations was also evaluated by analytical disc electrophoresis at pH 8.9. The purified hormone preparations had radioimmunological activity as follows: LH: 20 000 IU/mg, FSH: 16 500 IU/mg and TSH: 5 IU/mg. All preparations had high biological potency.


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