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Chemical modification of Aspergillus niger β-glucosidase and its catalytic properties

Aspergillus niger β-glucosidase was modified by covalent coupling to periodate activated polysaccharides (glycosylation). The conjugated enzyme to activated starch showed the highest specific activity (128.5 U/mg protein). Compared to the native enzyme, the conjugated form exhibited: a higher optima...

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Autores principales: Ahmed, Samia A., El-Shayeb, Nefisa M.A., Hashem, Abdel-Gawad M., Saleh, Shireen A.A., Abdel-Fattah, Ahmed F.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Sociedade Brasileira de Microbiologia 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4512046/
https://www.ncbi.nlm.nih.gov/pubmed/26221085
http://dx.doi.org/10.1590/S1517-838246120120462
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author Ahmed, Samia A.
El-Shayeb, Nefisa M.A.
Hashem, Abdel-Gawad M.
Saleh, Shireen A.A.
Abdel-Fattah, Ahmed F.
author_facet Ahmed, Samia A.
El-Shayeb, Nefisa M.A.
Hashem, Abdel-Gawad M.
Saleh, Shireen A.A.
Abdel-Fattah, Ahmed F.
author_sort Ahmed, Samia A.
collection PubMed
description Aspergillus niger β-glucosidase was modified by covalent coupling to periodate activated polysaccharides (glycosylation). The conjugated enzyme to activated starch showed the highest specific activity (128.5 U/mg protein). Compared to the native enzyme, the conjugated form exhibited: a higher optimal reaction temperature, a lower Ea (activation energy), a higher K (m) (Michaelis constant) and Vmax (maximal reaction rate), and improved thermal stability. The calculated t (1/2) (half-life) values of heat in-activation at 60 °C and 70 °C were 245.7 and 54.5 min respectively, whereas at these temperatures the native enzyme was less stable (t (1/2) of 200.0 and 49.5 min respectively). The conjugated enzyme retained 32.3 and 29.7%, respectively from its initial activity in presence of 5 mM Sodium Dodecyl Sulphate (SDS) and p -Chloro Mercuri Benzoate ( p -CMB), while the native enzyme showed a remarkable loss of activity (retained activity 1.61 and 13.7%, respectively). The present work has established the potential of glycosylation to enhance the catalytic properties of β-glucosidase enzyme, making this enzyme potentially feasible for biotechnological applications.
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spelling pubmed-45120462015-07-28 Chemical modification of Aspergillus niger β-glucosidase and its catalytic properties Ahmed, Samia A. El-Shayeb, Nefisa M.A. Hashem, Abdel-Gawad M. Saleh, Shireen A.A. Abdel-Fattah, Ahmed F. Braz J Microbiol Environmental Microbiology Aspergillus niger β-glucosidase was modified by covalent coupling to periodate activated polysaccharides (glycosylation). The conjugated enzyme to activated starch showed the highest specific activity (128.5 U/mg protein). Compared to the native enzyme, the conjugated form exhibited: a higher optimal reaction temperature, a lower Ea (activation energy), a higher K (m) (Michaelis constant) and Vmax (maximal reaction rate), and improved thermal stability. The calculated t (1/2) (half-life) values of heat in-activation at 60 °C and 70 °C were 245.7 and 54.5 min respectively, whereas at these temperatures the native enzyme was less stable (t (1/2) of 200.0 and 49.5 min respectively). The conjugated enzyme retained 32.3 and 29.7%, respectively from its initial activity in presence of 5 mM Sodium Dodecyl Sulphate (SDS) and p -Chloro Mercuri Benzoate ( p -CMB), while the native enzyme showed a remarkable loss of activity (retained activity 1.61 and 13.7%, respectively). The present work has established the potential of glycosylation to enhance the catalytic properties of β-glucosidase enzyme, making this enzyme potentially feasible for biotechnological applications. Sociedade Brasileira de Microbiologia 2015-03-01 /pmc/articles/PMC4512046/ /pubmed/26221085 http://dx.doi.org/10.1590/S1517-838246120120462 Text en Copyright © 2015, Sociedade Brasileira de Microbiologia All the content of the journal, except where otherwise noted, is licensed under a Creative Commons License CC BY-NC.
spellingShingle Environmental Microbiology
Ahmed, Samia A.
El-Shayeb, Nefisa M.A.
Hashem, Abdel-Gawad M.
Saleh, Shireen A.A.
Abdel-Fattah, Ahmed F.
Chemical modification of Aspergillus niger β-glucosidase and its catalytic properties
title Chemical modification of Aspergillus niger β-glucosidase and its catalytic properties
title_full Chemical modification of Aspergillus niger β-glucosidase and its catalytic properties
title_fullStr Chemical modification of Aspergillus niger β-glucosidase and its catalytic properties
title_full_unstemmed Chemical modification of Aspergillus niger β-glucosidase and its catalytic properties
title_short Chemical modification of Aspergillus niger β-glucosidase and its catalytic properties
title_sort chemical modification of aspergillus niger β-glucosidase and its catalytic properties
topic Environmental Microbiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4512046/
https://www.ncbi.nlm.nih.gov/pubmed/26221085
http://dx.doi.org/10.1590/S1517-838246120120462
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