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B Ersson

Publications and source records attributed to B Ersson.

At least 19 recordsLinked to original sources
PubMed2000

Purification, characterization and amino-acid sequence analysis of a thermostable, low molecular mass endo-beta-1,4-glucanase from blue mussel, Mytilus edulis.

A cellulase (endo-beta-1,4-D-glucanase, EC 3.2.1.4) from blue mussel (Mytilus edulis) was purified to homogeneity using a combination of acid precipitation, heat precipitation, immobilized metal ion affinity chromatography, size-exclusion chromatography and ion-exchange chromatography. Purity was analyzed by SDS/PAGE, IEF and RP-HPLC. The cellulase (endoglucanase) was characterized with regard to enzymatic properties, isoelectric point, molecular mass and amino-acid sequence. It is a single polypeptide chain of 181 amino acids cross-linked with six disulfide bridges. Its molecular mass, as measured by MALDI-MS, is 19 702 Da; a value of 19 710.57 Da was calculated from amino-acid composition. The isoelectric point of the enzyme was estimated by isoelectric focusing in a polyacrylamide gel to a value of 7.6. According to amino-acid composition, the theoretical pI is 7.011. The effect of temperature on the endoglucanase activity, with carboxymethyl cellulose and amorphous cellulose as substrates, respectively, was studied at pH 5.5 and displayed an unusually broad optimum activity temperature range between 30 and 50 degrees C. Another unusual feature is that the enzyme retains 55-60% of its maximum activity at 0 degrees C. The enzyme readily degrades amorphous cellulose and carboxymethyl cellulose but displays no hydrolytic activity towards crystalline cellulose (Avicel) and shows no cross-specificity for xylan; there is no binding to Avicel. The enzyme can withstand 10 min at 100 degrees C without irreversible loss of enzymatic activity. Amino-acid sequence-based classification has revealed that the enzyme belongs to the glycoside hydrolase family 45, subfamily 2 (B. Henrissat, Centre de Recherches sur les Macromolecules Végétales, CNRS, Joseph Fourier Université, Grenoble, France, personal communication).

Amino Acid Sequence↗
PubMed1999

Protein binding of mercury in milk and plasma from mice and man--a comparison between methylmercury and inorganic mercury.

Inorganic mercury has previously been shown to be excreted to milk from plasma to a higher extent than methylmercury. Protein binding of mercury as methylmercury and inorganic mercury in whey and plasma from mouse and man was studied in order to get a better understanding of the transport of mercury into milk. Mice were administered a single i.v. dose of 0.25 mg Hg/kg body weight labelled with (CH3)203HgCl or 203HgCl2, resulting in 11 ng Hg/g milk and 38 ng Hg/g milk after 1 h, respectively. Milk and plasma from mice and man were also incubated with the respective radiolabelled compound (150 ng Hg/g milk or plasma). Casein, fat and whey fractions in milk from methylmercury treated mice were found to contain 11, 39 and 34%, respectively, and from inorganic mercury treated mice 31, 15 and 41%, respectively, of the total amount of mercury in milk. Serum albumin was a major mercury binding protein in whey and plasma from mice for both methylmercury and inorganic mercury, as demonstrated by FPLC gel filtration and anion-exchange chromatography and further characterised by SDS-PAGE for whey. In addition, anion-exchange chromatography indicated that inorganic mercury, but not methylmercury, in whey from mouse milk formed a dimer of serum albumin. The unbound fraction of mercury in whey and plasma from mice was very small (<0.7%), and somewhat higher in plasma and whey from man. It is concluded, that the unbound fraction in plasma cannot be a determining factor for the observed differences in milk excretion between the two mercury compounds. Instead, it is suggested that methylmercury and to some extent inorganic mercury are transferred from plasma into milk using albumin as a passive carrier.

Adult↗
PubMed1996

Isolation of calcium-binding proteins on selective adsorbents. Application to purification of bovine calmodulin.

We report the fractionation of calcium-binding proteins using immobilized metal ion affinity chromatography (IMAC) with hard metal ions. Various hard metal ions (Mn2+, La3+, Nd3+, Eu(3 were immobilized on cross-linked agarose substituted with Tris(carboxymethyl)ethylenediamine (TED) and used as an adsorbent. After systematic studies, europium was selected for further work on the fractionation of calcium-binding proteins. It was found that the presence of Ca2+ in the sample and the solvent strongly promoted the adsorption and selectivity. Selective elution was accomplished in stepwise mode by the addition of calcium chelators such as malonate, citrate and phosphate. Calmodulin of high purity was isolated from a crude extract. Similar behavior of other calcium-binding proteins indicates that the reported chromatographic procedure can be generally applied to such proteins.

Adsorption↗
PubMed1989

Purification of two muscle enzymes by chromatography on immobilized ferric ions.

Two enzymes, glycogen phosphorylase and lactate dehydrogenase, were purified simultaneously in a single step. Ferric ions immobilized on a chelating gel were used as the adsorbent. Adsorption and desorption steps were accomplished by changes in buffer composition. The recoveries were better than 80% and the capacities were about 5 mg of protein per milliliter of adsorbent. The procedure worked well both on a small and on a preparative scale. The homogeneity of the purified enzymes was checked by FPLC.

Animals↗
PubMed1983

Dependence on cations for the binding activity of lectins as determined by affinity electrophoresis.

The metal ion content of eighteen different lectins was determined. The lectins were demetallized and the binding activity of native and demetallized forms were investigated using non-denaturing polyacrylamide affinity gel electrophoresis. The binding activities of all lectins were dependent on their metal ion content; when the cations were removed the lectins lost their carbohydrate binding activity. There was a marked difference in the strength with which lectins bind divalent cations.

Cations↗
PubMed1982

Lectins as inducers of interferon-gamma production in human lymphocytes: lentil lectin is highly efficient.

Several of many tested plant lectins induced interferon (IFN) production in cultures of human peripheral blood mononuclear leucocytes (PBL). The mannose-binding lectin obtained from Lens culinaris (LCL) was a particularly efficient inducer of trypsin-sensitive antiviral activity, which qualified as IFN-gamma because it was 90-95% destroyed by pH 2 treatment but not neutralized by anti-IFN-gamma antibodies. However, such antibodies neutralized the residual 5-10% pH 2-resistant IFN, which therefore represented IFN-alpha. Further evidence for the IFN-gamma nature of the LCL-induced IFN was that its production in PBL cultures required both T lymphocytes and macrophages and that its induction of antiviral resistance in human amnion cells was significantly delayed compared with IFN-alpha. Under optimal conditions LCL induced titres of IFN-gamma corresponding to more than 20,000 IFN-alpha units/ml medium, higher than observed with other tested, established IFN-gamma inducers. Other desirable properties of this lectin, as discussed, also suggest that it will be of value for efficient large-scale IFN-gamma production.

Humans↗
PubMed1979

Selective affinity fractionation of murine cytotoxic T lymphocytes (CTL). Unique lectin specific binding of the CTL associated surface glycoprotein, T 145.

We have analyzed the lectin binding characteristics of cytotoxic T lymphocyte (CTL)-derived surface labeled glycoproteins by affinity chromatography of the labeled glycoproteins on a panel of immobilized lectin adsorbents. Evidence is presented for the specific interaction of the CTL-associated glycoprotein T 145 with a lectin derived from Vicia villosa seeds. Conditions are described for the preparation and use of lectin affinity adsorbents for the rapid isolation of T 145 bearing cytotoxic T lymphocytes. Direct proof is given to show that T 145-positive cells arising from a variety of T-cell activations constitute the only subpopulation of cells with ability to perform cell-mediated T-cell cytotoxicity. Specific depletion of the CTLs by adherence to V. villosa adsorbents is shown by their depletion in the nonbound cell fraction and correspondingly enriched recovery in the sugar eluted cell fraction. Specific affinity fractionation of CTLs has occurred in every strain combination tested and irrespective of the actual antigen specificity of the effector cell population.

Animals↗
PubMed1979

Unique lectin-binding characteristics of cytotoxic T lymphocytes allowing their distinction from natural killer cells and "K" cells.

Cytotoxic T lymphocytes (CTL) can be selectively depleted from in vitro of in vivo alloactivated populations of T cells on Vicia villosa lectin adsorbents through the lectin-specific interaction with the CTL-associated surface glycoprotein T 145 (Kimura, A, Wigzell, H. and Holmquist, G., J. Exp. Med. 1979. 149: 473). Results from these and other experiments have demonstrated the general applicability of this fractionation procedure in which no constraints related to antigenic specificity of the CTL have been observed. When this fractionation procedure was applied to other compartments of cytolytic cells (natural killer cells and "K" cells), no detectable impact could be seen. This differential lectin binding would appear to offer a means of dissecting the activities of CTL from other compartments of cytolytic lymphoid cells.

Animals↗
PubMed1977

A phytohemagglutinin from Sunn hemp seeds (Crotalaria juncea). II. Purification by a high capacity biospecific affinity adsorbent and its physicochemical properties.

A galactose-specific lectin from seeds of Sunn Hemp (Crotalaria juncea) has been purified by fractional precipitation with ammonium sulfate followed by biospecific affinity chromatography and preparative isoelectric focusing. The adsorbent was prepared by coupling galactose to Sepharose 6B activated with divinyl sulfone. The lectin was homogeneous as judged by ultracentrifugation and by electrophoresis in cellulose acetate strips and in polyacrylamide gradient gel. Its isoelectric point is pH 8.8 and the molecular weight is about 120 000. It is a glycoprotein containing 9.8% also carbohydrate (mannose, N-acetyl-D-glucosamine, fucose, and xylose). The lectin contains 3.2 mol Ca2+, 2.2 mol Mg2+ and 0.2 mol Mn2+ per 120 000 g. No sulphur-containing amino acids were detected.

Amino Acids↗