Purification and properties of trehalase in Frankia ArI3 |
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Authors: | Mary F Lopez John G Torrey |
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Institution: | (1) Department of Botany, University of Massachusetts, 01003 Amherst, MA, USA;(2) Cabot Foundation, Harvard University, 01366 Petersham, MA, USA |
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Abstract: | Trehalase was purified from cultures of Frankia strain ArI3 grown on media with or without NH4Cl. The purified enzyme was specific for trehalose, exhibited a broad pH optimum of pH 4.5 to 5.3 and had a K
m for trehalose of 4.2 mM. The trehalase was inhibited in vitro completely by sucrose, glucose and mannose and partially by mannitol and sorbitol. In addition to the specific trehalase, a mixture of non-specific - and -glucosidases which exhibited some activity with , -trehalose as a substrate were also partially purified in Frankia extracts made from nitrogen-fixing cells. These enzymes were not detected in the purifications of crude extracts made from non-nitrogen-fixing cells (grown on media supplemented with NH4Cl). Trehalase activity in crude extracts increased over time when cells were induced to fix nitrogen, and the maximum specific activity of trehalase from nitrogen-fixing cultures was 4 times the maximum activity from non-fixing cultures. Trehalase activity was also examined in crude extracts made from Frankia vesicle clusters isolated from Alnus rubra nitrogen-fixing nodules infected with ArI3. The maximum activity of trehalase in these clusters was 6–7 times greater than in the nitrogenfixing pure cultures of ArI3 and 26–33 times greater than the non-fixing pure cultures.Abbreviations pcv
packed cell volume
- DTE
dithioerythritol
- PMSF
phenylmethylsulphonylfluoride
- EDTA
sodium ethylenediaminetetraacetate |
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Keywords: | Frankia Trehalose Trehalase Nitrogen-fixation Carbon metabolism |
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