Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sea urchin embryos were labeled with [3H]adenosine at two developmental stages (morula and prism) and the labeled acid-soluble nucleotides were fractionated successively by column chromatography with DEAE-Sephadex and DEAE-cellulose, and by thin-layer chromatography on a PEI-cellulose plate. Significant radioactivity was detected on the PEI-cellulose plate at the region of diadenosine 5',5'''-P1,P4-tetraphosphate (AP4A). After treatment of this fraction with phosphodiesterase, the radioactivity was all recovered in the AMP region, while alkaline phosphatase had no effect on the AP4A fraction. The present result suggests that AP4A is actively synthesized in the sea urchin embryos.
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PMID:Synthesis of diadenosine 5',5'''-P1,P4-tetraphosphate (AP4A) in sea urchin embryos. 672 90

The goal of the present work is to apply the versatile asymmetrical flow field-flow fractionation (AF4) coupled to UV and light scattering detection for the characterization of hyperbranched poly(ethylene imine) decorated with maltose shell (PEI-Mal) and the polar dye Rose Bengal (RB) in respect to their complexation behaviour. The quantitative determination of the non-complexed dye was carried out using the ultra-filtration effect of AF4 during the focussing phase, whereas the non-bound RB is filtrated and transported out of the channel while the complex of RB and PEI-Mal remains inside. A calibration with UV detector (550 nm) was established and different parameters (e.g. membrane material, molecular weight cut-off and stability of both, pure RB and RB@PEI-Mal complexes in solution) were investigated and verified. Successful reproducibility tests were performed. First complexation studies with the developed method were applied successfully with different mixture compositions of RB and PEI-Mal.
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PMID:An alternative route to dye-polymer complexation study using asymmetrical flow field-flow fractionation. 2054 76

In the field of nanomedicine, cationic polymers are the subject of intensive research and represent promising carriers for genetic material. The detailed characterization of these carriers is essential since the efficiency of gene delivery strongly depends on the properties of the used polymer. Common characterization methods such as size exclusion chromatography (SEC) or mass spectrometry (MS) suffer from problems, e.g. missing standards, or even failed for cationic polymers. As an alternative, asymmetrical flow field-flow fractionation (AF4) was investigated. Additionally, analytical ultracentrifugation (AUC) and (1)H NMR spectroscopy, as well-established techniques, were applied to evaluate the results obtained by AF4. In this study, different polymers of molar masses between 10 and 120kgmol(-1) with varying amine functionalities in the side chain or in the polymer backbone were investigated. To this end, some of the most successful gene delivery agents, namely linear poly(ethylene imine) (LPEI) (only secondary amines in the backbone), branched poly(ethylene imine) (B-PEI) (secondary and tertiary amino groups in the backbone, primary amine end groups), and poly(l-lysine) (amide backbone and primary amine side chains), were characterized. Moreover, poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA), poly(2-(amino)ethyl methacrylate) (PAEMA), and poly(2-(tert-butylamino)ethyl methacrylate) (PtBAEMA) as polymers with primary, secondary, and tertiary amines in the side chain, have been investigated. Reliable results were obtained for all investigated polymers by AF4. In addition, important factors for all methods were evaluated, e.g. the influence of different elution buffers and AF4 membranes. Besides this, the correct determination of the partial specific volume and the suppression of the polyelectrolyte effect are the most critical issues for AUC investigations.
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PMID:Characterization of cationic polymers by asymmetric flow field-flow fractionation and multi-angle light scattering-A comparison with traditional techniques. 2438 Jun 56