32 research outputs found
Heparanase enzymatic activity is required for reduction of syndecan-1 levels in the nucleus.
<p>Nuclear and non-nuclear fractions were prepared from CAG cells expressing high levels of wild-type heparanase (HPSE-high) or heparanase mutated at either amino acid 343 (M343) or amino acid 225 (M225) which renders them enzymatically inactive. All cells were prepared using pIRES<sub>2</sub> vectors for transfections. Fractions were analyzed for syndecan-1 levels by A) western blotting and B) ELISA. Grey bars = non-nuclear fraction; Black bars = nuclear fraction. Error bars represent standard error of the mean. *, <i>P</i><0.01 vs. nuclear syndecan-1 in HPSE high cells.</p
Exogenous recombinant heparanase (rHPSE) decreases nuclear syndecan-1 levels in a concentration-dependent manner.
<p>Recombinant heparanase was added to CAG cells having very low levels of heparanase expression (shRNA knockdown cells). Nuclear and non-nuclear fractions were prepared and syndecan-1 levels analyzed by A) western blotting and B) ELISA. Grey bars = non-nuclear fraction; Black bars = nuclear fraction. Error bars represent standard error of the mean. *, <i>P</i><0.01 vs. nuclear syndecan-1 in cells treated with 0 ng/ml rHPSE.</p
Elevated expression of heparanase dramatically decreases the level of syndecan-1 present within the nucleus.
<p>A) Nuclear and non-nuclear fractions were isolated from HPSE-low and HPSE-high cells (prepared using the pcDNA3 vector for transfections) and separated on SDS-PAGE. Western blots were probed with antibody to human syndecan-1, human heparanase, SP-1 or actin. B) Nuclear and non-nuclear fractions were isolated from HPSE-low and HPSE-high cells (prepared using the pIRES<sub>2</sub> vector for transfections) and from wild-type CAG cells infected with control shRNA or an shRNA targeting heparanase. The quantity of syndecan-1 in each fraction was determined by ELISA. Grey bars = non-nuclear fraction; Black bars = nuclear fraction. Error bars represent standard error of the mean. *, <i>P</i><0.01 vs. nuclear syndecan-1 in HPSE low cells; **, <i>P</i><0.02 vs. nuclear syndecan-1 in shRNA control.</p
Syndecan-1 is not detected within the nucleus of cells expressing high levels of heparanase.
<p>Confocal microscopic z-stack images of (A) HPSE-low and (B) HPSE-high cells immunostained using antibody to syndecan-1. Blue (Hoechst stain) identifies nuclei; white identifies syndecan-1 within the nucleus (co-localization of Hoechst and syndecan-1); green identifies cytoplasmic and cell surface syndecan-1. Syndecan-1 is detected within nuclei of HPSE-low cells but absent in nuclei of the HPSE-high cells. Bar = 10 µm. Note: As is characteristic of myeloma cells, the size of the nucleus is large relative to the amount of cytoplasm.</p
Efficient continuous kinetic resolution of racemic 2-aminobutanol over immobilized penicillin G acylase
<p>In this paper, an efficient method was established for continuous kinetic resolution of racemic 2-aminobutanol by selective hydrolysis of N-phenylacetyl (±)-2-aminobutanol over immobilized penicillin G acylase (PGA) in a fixed-bed reactor. Several N-acylated derivatives of 2-aminobutanol were screened in batch experiments, and it was found that the hydrolysis of N-phenylacetyl (±)-2-aminobutanol proceeded smoothly in the presence of immobilized penicillin G acylase with satisfied enantioselectivity. Thus, the reaction parameters were optimized in a fixed-bed reactor. Under the optimized conditions, 39.3% conversion of N-phenylacetyl (±)-2-aminobutanol and 98.2% ee value of S-2-aminobutanol were obtained. This fixed-bed system was operated continuously for 40 h without significant decrease of enzyme activity. It has been demonstrated to be more efficient compared to the batch experiments.</p
Iron(III)-Modified Tungstophosphoric Acid Supported on Titania Catalyst: Synthesis, Characterization, and Friedel–Craft Acylation of <i>m</i>‑Xylene
The
Friedel–Craft acylation of <i>m</i>-xylene
with benzoyl chloride over iron-modified tungstophosphoric acid supported
on titania was investigated. It was found that FeTPA/TiO<sub>2</sub> catalyst displayed excellent catalytic performance for this reaction.
Furthermore, a series of catalysts were prepared and characterized
by FT-IR, XRD, BET, NH<sub>3</sub>-TPD, and Py-IR. The results indicated
that both the Lewis acidity and the textural properties presented
significant influences on their catalytic performance. Moreover, the
influence of catalyst calcination temperature to the above reaction
was also studied. The reaction parameters, including reaction temperature,
catalyst dose, and molar ratio of <i>m</i>-xylene to benzoyl
chloride, were optimized, and a 95.1% yield of 2,4-dimethylbenzophenone
was obtained under optimal conditions. Finally, the kinetics of the
benzoylation of <i>m</i>-xylene over 30% FeTPA/TiO<sub>2</sub> was established
Synthesis of Hindered Phenolic Esters over Ion-Exchange Resins
<div><p></p><p>The esterification of 3,5-di-<i>tert</i>-butyl-4-hydroxybenzoic acid with 1-hexadecanol over a series of ion-exchange resins was investigated, in which resin D072 exhibited excellent catalytic performance. The influence of water on the reaction was also investigated, and it was found that water could improve the selectivity and increase the yield of the target product. Treatment of resins with aqueous sodium hydroxide could improve the selectivity of the target product but remarkably decreased the conversion of 3,5-di-<i>tert</i>-butyl-4-hydroxybenzoic acid. This result indicated that strong Brønsted acid sites played an important role in the reaction. Furthermore, D072 was efficiently recycled four runs by simple treatment with mineral acid. Finally, a series of hindered phenolic esters were successfully synthesized under the optimal reaction conditions. Therefore, a simple and versatile method for the synthesis of hindered phenolic esters has been established over ion-exchange resins and the target products were obtained in good yields.</p>
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Efficient synthesis of (S,S)-2,8-diazabicyclo[4.3.0]nonane
<p>An efficient synthetic route for moxifloxacin chiral intermediate via five steps was established. First, dehydration, <i>N</i>-acylation, and cyclization were combined in one pot to meet the industrial requirement. Then relatively low hydrogen pressure was employed in the catalytic hydrogenation reaction with high yield. Isopropanol/water system was used in resolution, which guaranteed high yield and perfect optical purity. The racemic process conducted by manganese dioxide and Pd/C successfully converted the undesired enantiomer into the racemate and hence the total yield increased remarkably. Furthermore, mild hydrogen transfer catalytic hydrogenation method was utilized in debenzylation process instead of high-pressure hydrogenation. Total yield of 39.0% was achieved, which was much higher than that of 29.0% in literature.</p
Hydroarylation of Styrenes with Electron-Rich Arenes Over Acidic Ion-Exchange Resins
<div><p></p><p>A series of acidic cation-exchange resins were used for the hydroarylation of resorcinol with styrene, in which resin D072 exhibited the excellent catalytic performance in this reaction with 99% conversion of styrene and 90% selectivity of 4-(1-phenylethyl)resorcinol. It was applied to the hydroarylation of various electron-rich arenes with styrenes, and the hydroarylated products were quantitatively obtained. This catalyst could be used for four consecutive runs with slight decrease in activity. The hydroarylation of resorcinol with styrene over resin D072 in a fixed bed was completed effectively with 94% selectivity and 99% conversion, and this green continuous process is potentially applicable to large-scale productions.</p>
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Hydrogenation of Aldehydes and Ketones to Corresponding Alcohols with Methylamine Borane in Neat Water
<div><p></p><p>Chemoselective hydrogenation of various aldehydes and ketones with methylamine borane (MeAB) in neat water was investigated. MeAB is suitable for green organic reactions, for MeAB is a nontoxic, environmentally benign, and easily handled reagent. Aldehydes were selectively and rapidly hydrogenated in excellent yields (86–97%) for 30 min, but hydrogenation of aromatic ketones needed over 20 h at room temperature because of their poor water solubility and steric hindrance. Thus we investigated polyethylene glycol (PEG400) and acidic cation-exchange D072 resin as catalysts to accelerate the hydrogenation reaction of aromatic ketones and achieved excellent yields within several hours. PEG 400 and D072 resin are both suitable for green organic reactions. The D072 resin was reused up to four times without any significance loss in activity.</p>
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