PubMed · 112384
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
B Schöning. 1979-05-11. [How dangerous are dextrans?].. https://pubmed.ncbi.nlm.nih.gov/112384/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Recently, branching sucrases encoded in the genomes of certain Lactic Acid Bacteria (LAB) strains have become novel enzymes to obtain branched α-glucans. In this study an active α-(1 → 2) branching sucrase from Apilactobacillus kunkeei PDER37 was expressed, characterised and distinct branched dextrans was obtained with reactions under different sucrose: dextran ratio. Structural characterisation by 1H and 13C NMR analysis demonstrated the branching of the dextran with (1 → 2)-linked α-d-glucose units with no alteration in the final structure depending on sucrose: dextran ratio (D0) but this ratio was effective for the determination of the molecular weights of the branched dextrans (D1, D2 and D3). FTIR analysis further supported the dextran structures and suggested the higher accumulation of the α-Glc units in the branched dextrans. Thermal characterisation of the branched dextrans obtained by TGA and DSC analysis suggested the increased hygroscopicity of the branching units. Both SEM and AFM analysis demonstrated more porous chain like structures in the branched dextrans. This study provides valuable information on the role of active α-(1 → 2) branching sucrase (BS37) for the production of branched dextrans with potential increased physicochemical status applicable for food and other industries.
We demonstrate in vitro the occurrence of a specific but low-affinity interaction between soluble tetrameric rgp160 or soluble monomeric or tetrameric rgp120 and heparin-agarose (HA). This interaction is saturable, pH and temperature-dependent, and can be inhibited by soluble heparin, but not by soluble dextran. In buffer supplemented with 10 mM CaCl2, the C50 of soluble heparin, i.e., the concentration of soluble heparin which leads to 50% inhibition of the binding of [125I]rgp160 or of [125I]rgp120 to HA, is 1.1 x 10(-4) disaccharidic molar concentration for rgp160 and 3.2 x 10(-4) dissacharidic molar concentration for rgp120, which indicates low-affinity interactions. Upon chromatography on HA, [125I]rgp160 is repeatedly eluted as a retarded fraction when compared to the elution volume of [125I]rgp160-soluble heparin complex. Under the same experimental conditions, [125I]rgp120 is also eluted, but as a less retarded fraction than [125I]rgp160. Taken together, these results suggest that, at least part of the described anti HIV-1 activity of heparin might be mediated by interaction with HIV-1 major envelope glycoprotein.
This paper demonstrates the use of UV-transparent replaceable polymer networks for the separation of SDS-protein complexes on the basis of molecular weight. First, the use of linear (i.e. non-cross-linked) polyacrylamide is shown to provide molecular separation of SDS-protein complexes. A study reveals such columns to yield significantly greater lifetime than cross-linked gels because of the flexibility of the noncovalently attached polymer chains. However, column lifetime was still found to be limited (approximately 20-40 injections), and detection at 214 nm was problematical because of the absorbance of polyacrylamide. UV-transparent polymer networks of dextran and PEG were substituted for polyacrylamide with successful molecular weight sieving of SDS-protein complexes at 214 nm. Due to their low to moderate viscosities, these networks could be routinely replaced leading to the possibility of hundreds of injections with a single column. Migration time reproducibilities of 0.5% RSD or less were found with replacement of the network. Using dextran, calibration plots of peak area vs concentration of standard protein were linear over the range of 0.5 microgram/mL up to at least 0.25 mg/mL. Furthermore, plasma samples could be directly utilized because of the strong solvating power of SDS. Rapid separation of protein mixtures are demonstrated with these UV-transparent polymer networks.