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Study of enzymatic properties of phenol oxidase from nitrogen-fixing Azotobacter chroococcum

Azotobacter chroococcum is a widespread free-living soil bacterium within the genus of Azotobacter known for assimilation of atmospheric nitrogen and subsequent conversion into nitrogenous compounds, which henceforth enrich the nitrogen content of soils. A. chroococcum SBUG 1484, isolated from compo...

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Autores principales: Herter, Susanne, Schmidt, Marlen, Thompson, Mark L, Mikolasch, Annett, Schauer, Frieder
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer 2011
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3402154/
https://www.ncbi.nlm.nih.gov/pubmed/21906365
http://dx.doi.org/10.1186/2191-0855-1-14
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author Herter, Susanne
Schmidt, Marlen
Thompson, Mark L
Mikolasch, Annett
Schauer, Frieder
author_facet Herter, Susanne
Schmidt, Marlen
Thompson, Mark L
Mikolasch, Annett
Schauer, Frieder
author_sort Herter, Susanne
collection PubMed
description Azotobacter chroococcum is a widespread free-living soil bacterium within the genus of Azotobacter known for assimilation of atmospheric nitrogen and subsequent conversion into nitrogenous compounds, which henceforth enrich the nitrogen content of soils. A. chroococcum SBUG 1484, isolated from composted earth, exhibits phenol oxidase (PO) activity when growing under nitrogen-fixing conditions. In the present study we provide incipient analysis of the crude PO activity expressed by A. chroococcum SBUG 1484 within comparative analysis to fungal crude PO from the white-rot fungus Pycnoporus cinnabarinus SBUG-M 1044 and tyrosinase (PPO) from the mushroom Agaricus bisporus in an attempt to reveal desirable properties for exploitation with future recombinant expression of this enzyme. Catalytic activity increased with pre-incubation at 35°C; however 70% of activity remained after pre-treatment at 50°C. Native A. chroococcum crude PO exhibited not only strong preference for 2,6-dimethoxyphenol, but also towards related methoxy-activated substrates as well as substituted ortho-benzenediols from over 40 substrates tested. Presence of CuSO(4 )enhanced crude phenol oxidase activity up to 30%, whereas NaN(3 )(0.1 mM) was identified as the most inhibiting substance of all inhibitors tested. Lowest inhibition of crude PO activity occurred after 60 minutes of incubation in presence of 15% methanol and ethanol with 63% and 77% remaining activities respectively, and presence of DMSO even led to increasing oxidizing activities. Substrate scope and inhibitor spectrum strongly differentiated A. chroococcum PO activity comprised in crude extracts from those of PPO and confirmed distinct similarities to fungal PO.
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spelling pubmed-34021542012-07-24 Study of enzymatic properties of phenol oxidase from nitrogen-fixing Azotobacter chroococcum Herter, Susanne Schmidt, Marlen Thompson, Mark L Mikolasch, Annett Schauer, Frieder AMB Express Original Azotobacter chroococcum is a widespread free-living soil bacterium within the genus of Azotobacter known for assimilation of atmospheric nitrogen and subsequent conversion into nitrogenous compounds, which henceforth enrich the nitrogen content of soils. A. chroococcum SBUG 1484, isolated from composted earth, exhibits phenol oxidase (PO) activity when growing under nitrogen-fixing conditions. In the present study we provide incipient analysis of the crude PO activity expressed by A. chroococcum SBUG 1484 within comparative analysis to fungal crude PO from the white-rot fungus Pycnoporus cinnabarinus SBUG-M 1044 and tyrosinase (PPO) from the mushroom Agaricus bisporus in an attempt to reveal desirable properties for exploitation with future recombinant expression of this enzyme. Catalytic activity increased with pre-incubation at 35°C; however 70% of activity remained after pre-treatment at 50°C. Native A. chroococcum crude PO exhibited not only strong preference for 2,6-dimethoxyphenol, but also towards related methoxy-activated substrates as well as substituted ortho-benzenediols from over 40 substrates tested. Presence of CuSO(4 )enhanced crude phenol oxidase activity up to 30%, whereas NaN(3 )(0.1 mM) was identified as the most inhibiting substance of all inhibitors tested. Lowest inhibition of crude PO activity occurred after 60 minutes of incubation in presence of 15% methanol and ethanol with 63% and 77% remaining activities respectively, and presence of DMSO even led to increasing oxidizing activities. Substrate scope and inhibitor spectrum strongly differentiated A. chroococcum PO activity comprised in crude extracts from those of PPO and confirmed distinct similarities to fungal PO. Springer 2011-06-24 /pmc/articles/PMC3402154/ /pubmed/21906365 http://dx.doi.org/10.1186/2191-0855-1-14 Text en Copyright ©2011 Herter et al; licensee Springer. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Original
Herter, Susanne
Schmidt, Marlen
Thompson, Mark L
Mikolasch, Annett
Schauer, Frieder
Study of enzymatic properties of phenol oxidase from nitrogen-fixing Azotobacter chroococcum
title Study of enzymatic properties of phenol oxidase from nitrogen-fixing Azotobacter chroococcum
title_full Study of enzymatic properties of phenol oxidase from nitrogen-fixing Azotobacter chroococcum
title_fullStr Study of enzymatic properties of phenol oxidase from nitrogen-fixing Azotobacter chroococcum
title_full_unstemmed Study of enzymatic properties of phenol oxidase from nitrogen-fixing Azotobacter chroococcum
title_short Study of enzymatic properties of phenol oxidase from nitrogen-fixing Azotobacter chroococcum
title_sort study of enzymatic properties of phenol oxidase from nitrogen-fixing azotobacter chroococcum
topic Original
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3402154/
https://www.ncbi.nlm.nih.gov/pubmed/21906365
http://dx.doi.org/10.1186/2191-0855-1-14
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