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1.
J Nanosci Nanotechnol ; 20(2): 789-801, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31383074

RESUMO

Magnetic Ni0.5Cu0.5Fe2O4/SiO2 nanocomposites were prepared via a solution combustion process, and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), Energy dispersive X-ray Spectroscopy (EDX) and vibrating sample magnetometer (VSM). The magnetic Ni0.5Cu0.5Fe2O4/SiO2 nanocomposites were employed to remove Congo red (CR) from aqueous solution, and the adsorption process was optimized by response surface methodology (RSM). The optimum conditions were the silica content of 12.6 wt%, the calcination temperature of 501 °C and the pH value of 7.13. The adsorption kinetics and the adsorption isotherm of CR onto magnetic Ni0.5Cu0.5Fe2O4/SiO2 nanocomposites at room temperature were investigated, and the intraparticle diffusion kinetics model and Redlich-Peterson isotherm model fitted well the respective process.

2.
Chin J Integr Med ; 24(3): 237-240, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26272547

RESUMO

Amarogentin is an efficacious Chinese herbal medicine and a component of the bitter apricot kernel. It is commonly used as an expectorant and supplementary anti-cancer drug. ß-Glucosidase is an enzyme that hydrolyzes the glycosidic bond between aryl and saccharide groups to release glucose. Upon their interaction, ß-glucosidase catalyzes amarogentin to produce considerable amounts of hydrocyanic acid, which inhibits cytochrome C oxidase, the terminal enzyme in the mitochondrial respiration chain, and suspends adenosine triphosphate synthesis, resulting in cell death. Hydrocyanic acid is a cell-cycle-stage-nonspecific agent that kills cancer cells. Thus, ß-glucosidase can be coupled with a tumor-specific monoclonal antibody. ß-Glucosidase can combine with cancer-cell-surface antigens and specifically convert amarogentin to an active drug that acts on cancer cells and the surrounding antibodies to achieve a killing effect. ß-Glucosidase is injected intravenously and recognizes cancer-cell-surface antigens with the help of an antibody. The prodrug amarogentin is infused after ß-glucosidase has reached the target position. Coupling of cell membrane peptides with ß-glucosidase allows the enzyme to penetrate capillary endothelial cells and clear extracellular deep solid tumors to kill the cells therein. The Chinese medicine amarogentin and ß-glucosidase will become an important treatment for various tumors when an appropriate monoclonal antibody is developed.


Assuntos
Amigdalina/uso terapêutico , Antineoplásicos/uso terapêutico , Pró-Fármacos/uso terapêutico , beta-Glucosidase/uso terapêutico , Anticorpos Monoclonais/uso terapêutico , Peptídeos Penetradores de Células/uso terapêutico , Humanos , Iridoides/uso terapêutico
3.
J Nanosci Nanotechnol ; 16(6): 6055-60, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27427671

RESUMO

Magnetic Fe3O4@SiO2 nanoparticles were prepared with molecular imprinting method using cellulase as the template. And the surface of the nanoparticles was chemically modified with arginine. The prepared nanoparticles were used as support for specific immobilization of cellulase. SDS-PAGE results indicated that the adsorption of cellulase onto the modified imprinted nanoparticles was selective. The immobilization yield and efficiency were obtained more than 70% after the optimization. Characterization of the immobilized cellulase revealed that the immobilization didn't change the optimal pH and temperature. The half-life of the immobilized cellulase was 2-fold higher than that of the free enzyme at 50 degrees C. After 7 cycles reusing, the immobilized enzyme still retained 77% of the original activity. These results suggest that the prepared imprinted nanoparticles have the potential industrial applications for the purification or immobilization of enzymes.


Assuntos
Celulase/química , Celulase/metabolismo , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Nanopartículas de Magnetita/química , Impressão Molecular , Dióxido de Silício/química , Animais , Arginina/química , Bovinos , Temperatura Ambiente
4.
Appl Microbiol Biotechnol ; 88(1): 49-55, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20567815

RESUMO

A one-pot, two-step enzymatic synthesis of amoxicillin from penicillin G, using penicillin acylase, is presented. Immobilized penicillin acylase from Kluyvera citrophila was selected as the biocatalyst for its good pH stability and selectivity. Hydrolysis of penicillin G and synthesis of amoxicillin from the 6-aminopenicillanic acid formed and D-p-hydroxyphenylglycine methyl ester were catalyzed in situ by a single enzyme. Zinc ions can react with amoxicillin to form complexes, and the yield of 76.5% was obtained after optimization. In the combined one-pot synthesis process, zinc sulfate was added to remove produced amoxicillin as complex for shifting the equilibrium to the product in the second step. By controlling the conditions in two separated steps, the conversion of the first and second step was 93.8% and 76.2%, respectively. With one-pot continuous procedure, a 71.5% amoxicillin yield using penicillin G was obtained.


Assuntos
Amoxicilina/metabolismo , Kluyvera/enzimologia , Penicilina Amidase/metabolismo , Zinco/metabolismo , Biotecnologia/métodos , Glicina/análogos & derivados , Glicina/metabolismo , Ácido Penicilânico/análogos & derivados , Ácido Penicilânico/metabolismo , Penicilina Amidase/isolamento & purificação , Penicilina G/metabolismo , Tecnologia Farmacêutica/métodos
5.
Prep Biochem Biotechnol ; 40(1): 38-45, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20024793

RESUMO

Enzymatic hydrolysis of penicillin G for production of 6-amino-penicillanic-acid (6-APA) was achieved by using penicillin G acylase as catalyst in an aqueous-methylisobutyl ketone (MIBK) system. The optimization was carried out and it was found that the best conversion was improved 10% more than the aqueous system, which was obtained at the conditions: initial pH 8.0, 5.0% (W/V) substrate (penicillin G), and temperature at 35 degrees C, and the ratio of aqueous and organic phase was 3:1. The stability of the biocatalyst was studied at the operational conditions. After 5 cycles of semi-batch reactions, the residual activity of penicillin G acylase was 69.2% of the initial activity. There was no apparent loss of the yield of product. This process has a potential application in the industrial scale production of 6-APA because it simplifies the process effectively.


Assuntos
Bacillus megaterium/enzimologia , Enzimas Imobilizadas/metabolismo , Ácido Penicilânico/análogos & derivados , Penicilina Amidase/metabolismo , Catálise , Hidrólise , Metil n-Butil Cetona/química , Ácido Penicilânico/metabolismo , Penicilina G/metabolismo , Água/química
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