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Enzyme characteristics of aminotransferase FumI of Sphingopyxis sp. MTA144 for deamination of hydrolyzed fumonisin B(1)
Fumonisins are carcinogenic mycotoxins that are frequently found as natural contaminants in maize from warm climate regions around the world. The aminotransferase FumI is encoded as part of a gene cluster of Sphingopyxis sp. MTA144, which enables this bacterial strain to degrade fumonisin B(1) and r...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Springer-Verlag
2011
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3136697/ https://www.ncbi.nlm.nih.gov/pubmed/21503761 http://dx.doi.org/10.1007/s00253-011-3248-9 |
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author | Hartinger, Doris Schwartz, Heidi Hametner, Christian Schatzmayr, Gerd Haltrich, Dietmar Moll, Wulf-Dieter |
author_facet | Hartinger, Doris Schwartz, Heidi Hametner, Christian Schatzmayr, Gerd Haltrich, Dietmar Moll, Wulf-Dieter |
author_sort | Hartinger, Doris |
collection | PubMed |
description | Fumonisins are carcinogenic mycotoxins that are frequently found as natural contaminants in maize from warm climate regions around the world. The aminotransferase FumI is encoded as part of a gene cluster of Sphingopyxis sp. MTA144, which enables this bacterial strain to degrade fumonisin B(1) and related fumonisins. FumI catalyzes the deamination of the first intermediate of the catabolic pathway, hydrolyzed fumonisin B(1). We used a preparation of purified, His-tagged FumI, produced recombinantly in Escherichia coli in soluble form, for enzyme characterization. The structure of the reaction product was studied by NMR and identified as 2-keto hydrolyzed fumonisin B(1). Pyruvate was found to be the preferred co-substrate and amino group receptor (K (M) = 490 μM at 10 μM hydrolyzed fumonisin B(1)) of FumI, but other α-keto acids were also accepted as co-substrates. Addition of the co-enzyme pyridoxal phosphate to the enzyme preparation enhanced activity, and saturation was already reached at the lowest tested concentration of 10 μM. The enzyme showed activity in the range of pH 6 to 10 with an optimum at pH 8.5, and in the range of 6°C to 50°C with an optimum at 35°C. The aminotransferase worked best at low salt concentration. FumI activity could be recovered after preincubation at pH 4.0 or higher, but not lower. The aminotransferase was denatured after preincubation at 60°C for 1 h, and the residual activity was also reduced after preincubation at lower temperatures. At optimum conditions, the kinetic parameters K (M) = 1.1 μM and k (cat) = 104/min were determined with 5 mM pyruvate as co-substrate. Based on the enzyme characteristics, a technological application of FumI, in combination with the fumonisin carboxylesterase FumD for hydrolysis of fumonisins, for deamination and detoxification of hydrolyzed fumonisins seems possible, if the enzyme properties are considered. |
format | Online Article Text |
id | pubmed-3136697 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2011 |
publisher | Springer-Verlag |
record_format | MEDLINE/PubMed |
spelling | pubmed-31366972011-08-26 Enzyme characteristics of aminotransferase FumI of Sphingopyxis sp. MTA144 for deamination of hydrolyzed fumonisin B(1) Hartinger, Doris Schwartz, Heidi Hametner, Christian Schatzmayr, Gerd Haltrich, Dietmar Moll, Wulf-Dieter Appl Microbiol Biotechnol Applied Microbial and Cell Physiology Fumonisins are carcinogenic mycotoxins that are frequently found as natural contaminants in maize from warm climate regions around the world. The aminotransferase FumI is encoded as part of a gene cluster of Sphingopyxis sp. MTA144, which enables this bacterial strain to degrade fumonisin B(1) and related fumonisins. FumI catalyzes the deamination of the first intermediate of the catabolic pathway, hydrolyzed fumonisin B(1). We used a preparation of purified, His-tagged FumI, produced recombinantly in Escherichia coli in soluble form, for enzyme characterization. The structure of the reaction product was studied by NMR and identified as 2-keto hydrolyzed fumonisin B(1). Pyruvate was found to be the preferred co-substrate and amino group receptor (K (M) = 490 μM at 10 μM hydrolyzed fumonisin B(1)) of FumI, but other α-keto acids were also accepted as co-substrates. Addition of the co-enzyme pyridoxal phosphate to the enzyme preparation enhanced activity, and saturation was already reached at the lowest tested concentration of 10 μM. The enzyme showed activity in the range of pH 6 to 10 with an optimum at pH 8.5, and in the range of 6°C to 50°C with an optimum at 35°C. The aminotransferase worked best at low salt concentration. FumI activity could be recovered after preincubation at pH 4.0 or higher, but not lower. The aminotransferase was denatured after preincubation at 60°C for 1 h, and the residual activity was also reduced after preincubation at lower temperatures. At optimum conditions, the kinetic parameters K (M) = 1.1 μM and k (cat) = 104/min were determined with 5 mM pyruvate as co-substrate. Based on the enzyme characteristics, a technological application of FumI, in combination with the fumonisin carboxylesterase FumD for hydrolysis of fumonisins, for deamination and detoxification of hydrolyzed fumonisins seems possible, if the enzyme properties are considered. Springer-Verlag 2011-04-19 2011 /pmc/articles/PMC3136697/ /pubmed/21503761 http://dx.doi.org/10.1007/s00253-011-3248-9 Text en © The Author(s) 2011 https://creativecommons.org/licenses/by-nc/4.0/ This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. |
spellingShingle | Applied Microbial and Cell Physiology Hartinger, Doris Schwartz, Heidi Hametner, Christian Schatzmayr, Gerd Haltrich, Dietmar Moll, Wulf-Dieter Enzyme characteristics of aminotransferase FumI of Sphingopyxis sp. MTA144 for deamination of hydrolyzed fumonisin B(1) |
title | Enzyme characteristics of aminotransferase FumI of Sphingopyxis sp. MTA144 for deamination of hydrolyzed fumonisin B(1) |
title_full | Enzyme characteristics of aminotransferase FumI of Sphingopyxis sp. MTA144 for deamination of hydrolyzed fumonisin B(1) |
title_fullStr | Enzyme characteristics of aminotransferase FumI of Sphingopyxis sp. MTA144 for deamination of hydrolyzed fumonisin B(1) |
title_full_unstemmed | Enzyme characteristics of aminotransferase FumI of Sphingopyxis sp. MTA144 for deamination of hydrolyzed fumonisin B(1) |
title_short | Enzyme characteristics of aminotransferase FumI of Sphingopyxis sp. MTA144 for deamination of hydrolyzed fumonisin B(1) |
title_sort | enzyme characteristics of aminotransferase fumi of sphingopyxis sp. mta144 for deamination of hydrolyzed fumonisin b(1) |
topic | Applied Microbial and Cell Physiology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3136697/ https://www.ncbi.nlm.nih.gov/pubmed/21503761 http://dx.doi.org/10.1007/s00253-011-3248-9 |
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