A highly thermostable trehalase from the thermophilic bacterium <Emphasis Type="Italic">Rhodothermus marinus</Emphasis> |
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Authors: | Carla D Jorge Maria Manuel Sampaio Gudmundur Ó Hreggvidsson Jakob K Kristjánson Helena Santos |
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Institution: | (1) Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Rua da Quinta Grande 6, Apartado 127, 2780-156 Oeiras, Portugal;(2) Prokaria Ltd, Gylfaflot 5, 112 Reykjavik, Iceland;(3) University of Iceland, Sudurgata, 101 Reykjavik, Iceland |
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Abstract: | Trehalases play a central role in the metabolism of trehalose and can be found in a wide variety of organisms. A periplasmic
trehalase (α,α-trehalose glucohydrolase, EC 3.2.1.28) from the thermophilic bacterium Rhodothermus marinus was purified and the respective encoding gene was identified, cloned and overexpressed in Escherichia coli. The recombinant trehalase is a monomeric protein with a molecular mass of 59 kDa. Maximum activity was observed at 88°C
and pH 6.5. The recombinant trehalase exhibited a K
m
of 0.16 mM and a V
max of 81 μmol of trehalose (min)−1 (mg of protein)−1 at the optimal temperature for growth of R. marinus (65°C) and pH 6.5. The enzyme was highly specific for trehalose and was inhibited by glucose with a K
i
of 7 mM. This is the most thermostable trehalase ever characterized. Moreover, this is the first report on the identification
and characterization of a trehalase from a thermophilic bacterium. |
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Keywords: | Rhodothermus marinus Periplasmic trehalase Glycosidase Thermostability |
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