scholarly journals The stability and aggregation properties of human liver acid β-d-galactosidase

1981 ◽  
Vol 193 (3) ◽  
pp. 773-779 ◽  
Author(s):  
C M Heyworth ◽  
E F Neumann ◽  
C H Wynn
Keyword(s):  
Ionic Strength ◽  
Molecular Form ◽  
Active Form ◽  
Gel Filtration ◽  
British Library ◽  
Fluorescence Excitation ◽  
Dimeric Form ◽  
The Stability ◽  
Low Ionic Strength ◽  
Beta Galactosidase

1. A method is described for following continuously the action of beta-galactosidase on 4-methylumbelliferyl beta-D-galactoside at pH 4.5, in which 4-methylumbelliferone production is measured at fluorescence excitation and emission wavelengths of 324 and 444nm respectively. 2. Initial-rate studies show that the presence of salt activates beta-galactosidase up to 100 mM, but is inhibitory above that concentration. The enzyme is very unstable at 37 degrees C and low ionic strength, but stability increases with ionic strength. 3. The stability of the enzyme at 37 degrees C decreases markedly with rising pH in the range 5.9–8.0. 4. Gel-filtration patterns demonstrate that there is a marked tendency to polymerization with increasing ionic strength. The gel-filtration pattern shows decreasing amounts of dimer with increasing pH. 5. The correlation between activity, stability and molecular form of beta-galactosidase is discussed. It is suggested that the dimeric form of the enzyme is the most stable and active form. The implications of this finding for the assay of beta-galactosidase under physiological conditions for prenatal diagnosis are discussed. 6. Evidence for the possible occurrence of a 36 000-mol.wt. from of beta-galactosidase is presented. 7. A computer program for the calculation of initial rates has been deposited as Supplementary Publication SUP 50114 (4 pages) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1981) 193, 5.

Aminoacyl-tRNA synthetases of Halobacterium cutirubrum: preliminary fractionation studies

1970 ◽  
Vol 48 (8) ◽  
pp. 944-946 ◽  
Author(s):  
E. Griffiths
Keyword(s):  
Ionic Strength ◽  
Gel Filtration ◽  
Halophilic Bacterium ◽  
Trna Synthetase ◽  
Partial Purification ◽  
Trna Synthetases ◽  
Aminoacyl Trna Synthetases ◽  
Fractionation Procedure ◽  
The Stability ◽  
Low Ionic Strength

The stability, in solutions of low ionic strength, of aminoacyl-tRNA synthetases from the extremely halophilic bacterium Halobacterium cutirubrum was studied as a preliminary to their fractionation. The enzymes differed considerably in their sensitivity to such solutions. Conditions were found where reactivation from the salt-free and inactive state could be achieved. Removal of both K+ and Mg2+ together generally resulted in better stability than the removal of K+ alone. A low temperature (4°) was also important for stability in buffers of low ionic strength. In some cases the L-amino acid substrates afforded protection against inactivation in the salt-free state. Gel filtration in low ionic strength medium was found to work well as a fractionation procedure; a partial purification of phenylalanyl-tRNA synthetase was effected in this way. The use of other conventional protein fractionation procedures is now possible.

scholarly journals The binding of human liver acid β-galactosidase to wheat-germ lectin is influenced by aggregation state of the enzyme

1982 ◽  
Vol 201 (3) ◽  
pp. 615-619 ◽  
Author(s):  
C M Heyworth ◽  
C H Wynn
Keyword(s):  
Ionic Strength ◽  
Human Liver ◽  
Wheat Germ ◽  
Gel Filtration ◽  
Aggregation State ◽  
Low Ionic Strength ◽  
Cellogel Electrophoresis ◽  
Wheat Germ Lectin ◽  
Beta Galactosidase

At low ionic strength and pH 6.0 human liver acid beta-galactosidase exists in two aggregation states, monomeric and multimeric. These species can be separated on wheat-germ lectin-Sepharose, Cellogel electrophoresis and gel filtration on Sephadex G-200, and are not normally interconvertible. On re-application of either form to wheat-germ lectin-Sepharose the equilibrium is re-established and the two forms are interconverted.

The aggregation and reaction with oxygen of the tetrasodium salt of cobalt phthalocyanine-4,4',4'',4'''-tetrasulphonic acid

1973 ◽  
Vol 26 (2) ◽  
pp. 319 ◽  
Author(s):  
LC Gruen ◽  
RJ Blagrove
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Molecular Oxygen ◽  
Absorption Spectra ◽  
Alkaline Solution ◽  
Cobalt Phthalocyanine ◽  
Visible Absorption ◽  
Reversible Addition ◽  
Dimeric Form ◽  
Low Ionic Strength

The reversible addition of molecular oxygen to the tetrasodium salt of cobalt phthalocyanine-4,4?,4?,4??-tetrasulphonic acid in aqueous solution has been confirmed. Visible absorption spectra of the monomeric and dimeric species and of the oxygen adduct have been determined. A monomer-dimer system prevails at neutral pH, low ionic strength, and low dye concentrations. The oxygen adduct and the dimeric form of the dye predominate in alkaline solution.

scholarly journals Hyaluronidase in ram semen. Quantitative determination, and isolation of multiple forms

1988 ◽  
Vol 252 (3) ◽  
pp. 865-874 ◽  
Author(s):  
R A Harrison
Keyword(s):  
Ionic Strength ◽  
Quantitative Determination ◽  
Specific Activity ◽  
Gel Filtration ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
High Yield ◽  
Poly Vinyl Alcohol ◽  
The Media ◽  
Low Ionic Strength

A study was made of hyaluronidase in ram semen. The end-group assay conditions used to determine activity quantitatively were chosen to ensure reliability as well as sensitivity [Gacesa, Savitsky, Dodgson & Olavesen (1981) Anal. Biochem. 118, 76-84]; they led to 1 W.H.O. Standard International Hyaluronidase Unit displaying 0.1263 EC munit (1 EC unit of activity releases 1 mumol equivalent of N-acetylglucosamine end groups/min at 37 degrees C). All the activity in the semen was shown to be sperm-derived, and intact spermatozoa were estimated to contain 1.23 EC units per 10(9) cells. In a low-ionic-strength medium, only some 20% of the hyaluronidase was extractable, although up to 80% of the activity could be extracted as the ionic strength was increased; further addition of detergent extracted the remainder. During purification of the enzyme, it was found that inclusion of poly(vinyl alcohol) in the media stabilized the activity; detergent inclusion also improved the yield, especially during early stages. As a consequence both of reliable quantitative determination and of stabilization, a number of forms of hyaluronidase could be isolated in high yield, by using anion-exchange chromatography, cation-exchange chromatography, affinity chromatography and gel filtration. The existence of all these forms was confirmed by electrophoresis and immunoblotting with the use of a monoclonal anti-(ram hyaluronidase) antibody, and their presence in very freshly prepared sperm extracts was demonstrated. The specific activity of the isolated major hyaluronidase form was 15.0 EC units/mg; this was equivalent to 119,000 W.H.O. units/mg, higher than any other previously reported values.

Human and Bovine Plasminogen-Free Thrombin, Purified by Means of Gel Filtration and Ion Exchange Chromatography

1966 ◽  
Vol 15 (03/04) ◽  
pp. 501-510 ◽  
Author(s):  
W Berg ◽  
K Korsan-Bengtsen ◽  
J Ygge
Keyword(s):  
Molecular Weight ◽  
Ionic Strength ◽  
Large Scale ◽  
Gel Filtration ◽  
Trisodium Citrate ◽  
Exchange Chromatography ◽  
Simple Method ◽  
Commercial Preparation ◽  
Usual Manner ◽  
Low Ionic Strength

SummaryA simple method for preparation of plasminogen-free human and bovine thrombin is described.Crude thrombin was prepared in the usual manner from oxalated plasma by means of adsorption on BaSO4, elution with trisodium citrate and activating the eluate from BaSO4 with tissue thromboplastin.This crude thrombin was purified by means of gel-filtration and chromatography on CM-Sephadex A-50.The gel-filtration was performed on three types of Sephadex, G-75, G-50, and G--25. By means of Sephadex G-75 the thrombin was well separated from the main part of inert protein and this type of Sephadex was used for the purification in large-scale. Separation of thrombin from protein of higher molecular weight was also obtained with Sephadex G-50 but not with Sephadex G-25 indicating a molecular weight of thrombin between 4000 and 10,000.The importance of using an elution buffer of sufficient high ionic strength for gel-filtration is shown. A great deal of the thrombin was adsorbed to the Sephadex if the gel-filtration was performed at a too low ionic strength.The final preparation contained 30,000 NIH units of thrombin per mg tyrosin and no detectable plasminogen.The commercial preparation “Topostasine” was also purified in the same manner, but the plasminogen content in “Topostasine” was high and could not be completely separated from thrombin.

scholarly journals Granulocyte/macrophage-, megakaryocyte-, eosinophil- and erythroid-colony-stimulating factors produced by mouse spleen cells

1980 ◽  
Vol 185 (2) ◽  
pp. 301-314 ◽  
Author(s):  
Antony W. Burgess ◽  
Donald Metcalf ◽  
Sue H. M. Russell ◽  
Nicos A. Nicola
Keyword(s):  
Ionic Strength ◽  
Isoelectric Focusing ◽  
Biological Activities ◽  
Gel Filtration ◽  
Maximum Activity ◽  
Colony Stimulating Factor ◽  
Colony Stimulating Factors ◽  
Molecular Weights ◽  
Low Ionic Strength ◽  
Stimulating Factor

The formation of mature haemopoietic cells is controlled by hormones that specifically stimulate the progenitor cells of the granulocyte/macrophage, eosinophil, megakaryocyte and erythroid pathways. PWMSC medium (pokeweed-mitogen-stimulated spleen-cell-conditioned medium) is known to contain the biological activities that control the clonal proliferation of these four progenitor cells in vitro in semi-solid agar cultures. In this study the molecular properties of these biological activities were characterized, and all four colony-stimulating factors appear to be associated with glycoproteins. These factors were precipitated between 50 and 80%-satd. (NH4)2SO4 and could be concentrated by ultrafiltration over a 10000-mol.wt.-cut-off hollow-fibre membrane. Megakaryocyte- and erythroid-colony-stimulating factors were lost when the conditioned medium was dialysed at low ionic strength (<0.03m). Neither asialo- nor sialo-erythropoietin was detectable in concentrated PWMSC medium or in the fractions purified from it by gel filtration on Sephadex G-150. The factors bound to concanavalin A–Sepharose were eluted with α-methyl-d-glucopyranoside (0.10m). Analysis by gel filtration on Sephadex G-150 indicated that the apparent molecular-weight distributions of all colony-stimulating factors were identical (37000). Treatment with neuraminidase did not alter the biological activities of any of these factors, but when the molecular weights were analysed, after neuraminidase treatment, on Sepharose CL-6B in the presence of guanidine hydrochloride (6m) all were eluted with a mol.wt. of 24000. Although the apparent molecular weights of the different factors were identical, charge differences were detectable by isoelectric focusing on thin-layer granulated gels. There appeared to be considerable charge heterogeneity associated with each factor, as all were focused over 2–4 pH units. The maximum activity of the granulocyte/macrophage-colony-stimulating factor on isoelectric focusing was at pH4.8, whereas the maximum activity for the eosinophil-colony-stimulating factor was at pH5.8. The erythroid- and megakaryocyte-colony-stimulating activities were detected in the pH ranges 4.8–5.8 and 4.6–7.1 respectively. Chromatographic differences between the granulocyte/macrophage- and eosinophil-colony-stimulating factors were also detected by hydrophobic chromatography at low ionic strength (0.15m-NaCl) on Cibacron Blue–Sepharose and at high ionic strength [2m-(NH4)2SO4] on phenyl-Sepharose. Eosinophil-colony-stimulating factor bound more strongly than the other factors to both matrices. The megakaryocyte- and erythroid-colony-stimulating activities were always associated with those for granulocytes/macrophages and eosinophils. Preparations highly enriched for eosinophil-colony-stimulating factor were also obtained by DEAE-cellulose chromatography. An overall purification of 100-fold for all of the factors was achieved with the present techniques, and, although differences were observed, only granulocyte/macrophage-stimulating factors and a small proportion of the eosinophil-stimulating factors could be completely separated from the others. Our results are consistent with the existence of separable factors for granulocyte/macrophage and eosinophil stimulation, but the megakaryocyte- and erythroid-stimulating activities were always associated with the granulocyte/macrophage- and eosinophil-stimulating activities. Thus there may be one molecule that is able to stimulate all four colony types or four very similar molecules that are difficult to separate.

scholarly journals Subunit composition and structure of subcomponent C1q of the first component of human complement

1976 ◽  
Vol 155 (1) ◽  
pp. 19-23 ◽  
Author(s):  
K B M Reid ◽  
R R Porter
Keyword(s):  
Ionic Strength ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Helical Structure ◽  
Guanidinium Chloride ◽  
Molecular Weights ◽  
Composition And Structure ◽  
Covalently Linked ◽  
Low Ionic Strength ◽  
Expected Position

1. Unreduced human subcomponent C1q was shown by electrophoresis on polyacrylamide gels run in the presence of sodium dodecyl sulphate to be composed of two types of non-covalently linked subunits of apparent mol.wts. 69 000 and 54 000. The ratio of the two subunits was markedly affected by the ionic strength of the applied sample. At a low ionic strength of applied sample, which gave the optimum value for the 54 000-apparent mol.wt. subunit, a ratio of 1.99:1.00 was obtained for the ratio of the 69 000-apparent mol.wt. subunit to the 5400-apparent-mol.wt. subunit. The amount of the 54 000-apparent-mol.wt. subunit detected in the expected position on the gel was found to be inversely proportional to increases in the ionic strength of the applled sample. 2. Human subcomponent C1q on reduction and alkylation, or oxidation, yields equimolar amounts of three chains designated A, B and C [Reid et al. (1972) Biochem. J. 130, 749-763]. The results obtained by Yonemasu & Stroud [(1972) Immunochemistry 9, 545-554], which showed that the 69 000-apparent-mol.wt. subunit was a disulphide-linked dimer of the A and B chains and that the 54 000-apparent-mol.wt. subunit was a disulphide-linked dimer of the C chain, were confirmed. 3. Gel filtration on Sephadex G-200 in 6.0M-guanidinium chloride showed that both types of unreduced subunit were eluted together as a single symmetrical peak of apparent mol.wt. 49 000-50 000 when globular proteins were used as markers. The molecular weights of the oxidized or reduced A, B and C chains have been shown previously to be very similar all being in the range 23 000-24 000 [Reid et al. (1972) Biochem. J. 130, 749-763; Reid (1974) Biochem. J. 141, 189-203]. 4. It is proposed that subcomponent C1q (mol.wt. 410000) is composed of nine non-covalently linked subunits, i.e. six A-B dimers and three C-C dimers. 5. A structure for subcomponent C1q is proposed and is based on the assumption that the collagen-like regions of 78 residues in each of the A, B and C chains are combined to form a triple-helical structure of the same type as is found in collagens.

Europium tartronate and mandelate ion association in water

1967 ◽  
Vol 45 (14) ◽  
pp. 1643-1647 ◽  
Author(s):  
P. G. Manning
Keyword(s):  
Ionic Strength ◽  
Solvent Extraction ◽  
Stability Constant ◽  
Stability Constants ◽  
Ion Association ◽  
Tridentate Ligand ◽  
Radiotracer Method ◽  
The Stability ◽  
Two Stages ◽  
Low Ionic Strength

Stepwise stability constants have been determined for the 1:1 and 1:2 Eu3+:mandelate− and Eu3+:tartronate2− complexes in water. Measurements were made at low ionic strength and the temperature was 25 °C. The solvent-extraction–radiotracer method was used.For the mandelate system at an ionic strength of 0.104, K1 = 5.0 × 102, K2 = 1.58 × 102, and K1:K2 = 3.1. The K1:K2 ratios suggest monodentate ligandcy.The stepwise stability constants for the two stages of tartronate ion association are: K1 = 7.1 ( ± 15%) × 104 and K1K2 = 4.2 ( ± 5%) × 108. The magnitudes of the stability constants suggest that tartronate is a tridentate ligand. The stability constant ratios are discussed with reference to the ratios for piperidinedicarboxylate and iminodiacetate complexes.

scholarly journals Higher-plant cyclic nucleotide phosphodiesterases. Resolution, partial purification and properties of three phosphodiesterases from potato tuber

1975 ◽  
Vol 149 (2) ◽  
pp. 329-339 ◽  
Author(s):  
A R Ashton ◽  
G M Polya
Keyword(s):  
Ionic Strength ◽  
Cyclic Amp ◽  
Cyclic Nucleotides ◽  
Cyclic Nucleotide ◽  
Higher Plants ◽  
Gel Filtration ◽  
Nucleotide Metabolism ◽  
Partial Purification ◽  
Higher Plant ◽  
Low Ionic Strength

1. Three phosphodiesterases that are capable of hydrolysing 3':5'-cyclic nucleotides were purified from potato tubers. 2. The phosphodiesterases were fractionated by (NH4)2SO4 precipitation and CM-cellulose chromatography. The phosphodiesterases were resolved from each other and further purified by gel filtration in high- and low-ionic-strength conditions. 3. All three enzymes lacked significant nucleotidase activity. 4. Enzymes I and II had mol. wts. 240,000 and 80,000 respectively, determined by gel filtration, whereas enzyme III showed anomalous behaviour on gel filtration, behaving as a high- or low-molecular-weight protein in high- or low-ionic-strength buffers respectively. 5. All enzymes hydrolysed 2':3'-cyclic nucleotides as well as 3':5'-cyclic nucleotides. The enzymes also had nucleotide pyrophosphatase activity, hydrolysing NAD+ and UDP-glucose to various extents. Enzymes I and II hydrolyse cyclic nucleotides at a greater rate than NAD+, whereas enzyme III hydrolyses NAD+ at a much greater rate than cyclic nucleotides. All three enzymes hydrolysed the artificial substrate bis-(p-nitro-phenyl) phosphate. 6. The enzymes do not require the addition of bivalent cations for activity. 7. Both enzymes I and II have optimum activity at pH6 with 3':5'-cyclic AMP and bis-(p-nitrophenyl) phosphate as substrates. The products of 3':5'-cyclic AMP hydrolysis were 3'-AMP and 5'-AMP, the ratio of the two products being different for each enzyme and varying with pH. 8. Theophylline inhibits enzymes I and II slightly, but other methyl xanthines have little effect. Enzymes I and II were competitively inhibited by many nucleotides containing phosphomonoester and phosphodiester bonds, as well as by Pi. 9. The possible significance of these phosphodiesterases in cyclic nucleotide metabolism in higher plants is discussed.

scholarly journals Characterization and localization of myosin in the brush border of intestinal epithelial cells

1978 ◽  
Vol 79 (2) ◽  
pp. 444-453 ◽  
Author(s):  
MS Mooseker ◽  
TD Pollard
Keyword(s):  
Ionic Strength ◽  
Epithelial Cells ◽  
Atpase Activity ◽  
Brush Border ◽  
Intestinal Epithelial Cells ◽  
Gel Filtration ◽  
Intestinal Epithelial ◽  
Terminal Web ◽  
Brush Borders ◽  
Low Ionic Strength

The brush border of intestinal epithelial cells consists of a tightly packed array of microvilli, each of which contains a core of actin filaments. It has been postulated that microvillar movements are mediated by myosin interactions in the terminal web with the basal ends of these actin cores (Mooseker, M.S. 1976. J. Cell. Biol. 71:417-433). We report here that two predictions of this model are correct: (a) The brush border contains myosin, and (b) myosin is located in the terminal web. Myosin is isolated in 70 percent purity by solubilization of Triton-treated brush borders in 0.6 M KI, and separation of the components by gel filtration. Most of the remaining contaminants can be removed by precipitation of the myosin at low ionic strength. This yield is approximately 1 mg of myosin/30 mg of solubilized brush border protein. The molecule consists of three subunits with molecular weights of 200,000, 19,000, and 17,000 daltons in a 1:1:1 M ratio. At low ionic strength, the myosin forms small, bipolar filaments with dimensions of 300 X 11nm, that are similar to filaments seen previously in the terminal web of isolated brush borders. Like that of other vertebrate, nonmuscle myosins, the ATPase activity of isolated brush border myosin in 0.6 M KCI is highest with EDTA (1 μmol P(i)/mg-min; 37 degrees C), intermediate with Ca++ (0.4 μmol P(i)/mg-min), and low with Mg++ (0.01 μmol P(i)/mg-min). Actin does not stimulate the Mg-ATPase activity of the isolated enzyme. Antibodies against the rod fragment of human platelet myosin cross-react by immunodiffusion with brush border myosin. Staining of isolated mouse or chicken brush borders with rhodamine-antimyosin demonstrates that myosin is localized exclusively in the terminal web.

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