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1.
Electrophoresis ; 36(9-10): 1179-85, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25753141

RESUMO

A method based on CZE for the determination of glutamic acid, glycine, and alanine in a biopharmaceutical formulation containing recombinant human erythropoietin was developed. The separation was achieved within less than 5 min, using a fused-silica capillary column (55 cm × 50 µm id) and 30 mmol/L phosphate buffer at pH 11.5, containing 0.6 mmol/L CTAB and 10% v/v methanol, as BGE solution. Applied potential of -25 kV, temperature of 15°C and hydrodynamic injection time of 15 s, at 50 mbar, were employed. The detection of the analytes was carried out without any derivatization reaction, at 220 nm using an UV-DAD detector. Linear ranges from 50 to 2500 mg/L and quantification limits of 40, 39, and 37 mg/L were obtained for glutamic acid, glycine, and alanine, respectively. Sample preparation required only a dilution step. Considering peak area and migration time values, the method presented good repeatability (RSD <1.7%; n = 9) and intermediate precision (RSD <1.0%; n = 6). Recovery evaluation using a commercial sample led to values between 97.5 ± 5.2% and 101.5 ± 4.6%, demonstrating the feasibility of the method, which was successfully applied in the quantification of the amino acids of interest in biopharmaceutical samples.


Assuntos
Aminoácidos/análise , Eritropoetina/química , Proteínas Recombinantes/química , Anemia/tratamento farmacológico , Eletroforese Capilar/métodos , Eritropoetina/análise , Eritropoetina/uso terapêutico , Humanos , Concentração de Íons de Hidrogênio , Limite de Detecção , Modelos Lineares , Proteínas Recombinantes/análise , Proteínas Recombinantes/uso terapêutico , Reprodutibilidade dos Testes
2.
Insect Biochem Mol Biol ; 43(10): 970-81, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23917163

RESUMO

Termites can degrade up to 90% of the lignocellulose they ingest using a repertoire of endogenous and symbiotic degrading enzymes. Termites have been shown to secrete two main glycoside hydrolases, which are GH1 (EC 3.2.1.21) and GH9 (EC 3.2.1.4) members. However, the molecular mechanism for lignocellulose degradation by these enzymes remains poorly understood. The present study was conducted to understand the synergistic relationship between GH9 (CgEG1) and GH1 (CgBG1) from Coptotermes gestroi, which is considered the major urban pest of São Paulo State in Brazil. The goal of this work was to decipher the mode of operation of CgEG1 and CgBG1 through a comprehensive biochemical analysis and molecular docking studies. There was outstanding degree of synergy in degrading glucose polymers for the production of glucose as a result of the endo-ß-1,4-glucosidase and exo-ß-1,4-glucosidase degradation capability of CgEG1 in concert with the high catalytic performance of CgBG1, which rapidly converts the oligomers into glucose. Our data not only provide an increased comprehension regarding the synergistic mechanism of these two enzymes for cellulose saccharification but also give insight about the role of these two enzymes in termite biology, which can provide the foundation for the development of a number of important applied research topics, such as the control of termites as pests as well as the development of technologies for lignocellulose-to-bioproduct applications.


Assuntos
Glicosídeo Hidrolases/metabolismo , Isópteros/enzimologia , Animais , Celulose/metabolismo , Glicosídeo Hidrolases/isolamento & purificação , Cinética , Simulação de Acoplamento Molecular , Proteínas Recombinantes/isolamento & purificação , Especificidade por Substrato
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