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Master's Dissertation
DOI
Document
Author
Full name
Diana Zukas Andreotti
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2010
Supervisor
Committee
Vitolo, Michele (President)
Queiroz, Alvaro Antonio Alencar de
Yagui, Carlota de Oliveira Rangel
Title in Portuguese
Regeneração de nucleotídeos β-nicotinamida adenínicos solúveis ou imobilizados em sistemas com enzimas acopladas
Keywords in Portuguese
Conversão multienzimática
Enzimologia
Glicose-6-fosfato desidrogenase
Glutamato desidrogenase
Imobilização de cofatores
Abstract in Portuguese
As bioconversões executadas com enzimas, que requerem NADP ou NADPH, são limitadas pela eficiência com que esta substância é mantida na forma particular requerida pelo catalisador ao longo de toda a reação, assim como pela sua recuperação no final do processo. Neste trabalho, foram caracterizadas as enzimas Glicose-6-fosfato desidrogenase (G6PDH) e Glutamato desidrogenase (GLUDH), além do estudo do reciclo NADP/NADPH em sistema constituído por essas enzimas. Determinou-se a temperatura (30ºC) e pH ótimo da G6PDH (pH 7,5), assim como a temperatura (40ºC) e o pH ótimo (pH 8,0) da GLUDH, além dos volumes e concentrações dos substratos utilizados na hidrólise enzimática. No caso da reação acoplada descontínua, a duração foi de 90min, às temperaturas de 30ºC e 40ºC, utilizando-se o cofator solúvel ou imobilizado. Em ambas as condições, mais de 85% das concentrações iniciais de G6P e NH4+, respectivamente, substratos da G6PDH e GLUDH, foram convertidas, sendo o reciclo NADP/NADPH mantido durante toda a reação. No caso da reação bienzimática em reator contínuo, não foi possível chegar ao estado estacionário da reação e a conversão dos subsratos G6P e NH4+ variaram de acordo com o período do teste.
Title in English
Regeneration of nucleotides β-nicotinamide adenine soluble or immobilized enzyme coupled systems.
Keywords in English
Cofactor immobilization
Enzymology
Glucose-6-phosphate dehydrogenase
Glutamate dehydrogenase
Multienzimatic conversion
Abstract in English
The Bioconversion performed with enzymes that require NADPH or NADP are limited by the efficiency with which this substance is maintained in the particular form required by the enzyme throughout the reaction, as well as for his recovery at the end of the process. The main aim of this work was to study the NADP/NADPH recycling through a bienzyme coupled reaction constituted by glucose-6-phosphate dehydrogenase (G6PDH) and glutamate dehydrogenase (GLUDH). The reaction was carried out in the discontinuous or continuous mode. The discontinuous process, which was carried out with soluble or immobilized NADP at 30°C or 40°C, had a total duration of 90min. Independently on the temperature used, around 85% of the initial concentration of glucose 6-phosphate (G6P) and ammonia were consumed, being the recycle of NADP/NADPH maintained throughout the reaction. In the continuous process, the addition of G6P and ammonia into the membrane reactor was made by turns of 2h. During the 15h-process the NADP/NADPH recycling was attained and the mean consumption yield of ammonia and G6P neared 30% and 60%, respectively.
 
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Publishing Date
2013-07-23
 
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