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J. Bacteriol., May 1995, 2721-2726, Vol 177, No. 10
S Gotsche and MK Dahl
The intracellular phospho-alpha(1,1)glucosidase TreA from Bacillus subtilis
has been overproduced in Escherichia coli and purified by ion- exchange
chromatography and gel filtration. The molecular mass, estimated by sodium
dodecyl sulfate-polyacrylamide gel electrophoresis, was 64 kDa. Isoelectric
focusing indicated homogeneity of the protein, and its pI was determined to
be 4.3. Characterization of the enzyme showed a protein which is stable up
to 44 degrees C after temperature treatment for 15 min. The temperature
optimum was found to be 37 degrees C, and the pH optimum was 4.5. TreA
activity is stimulated by high salt concentrations with different
efficiencies depending on the kind of salt. When increasing amounts of
ammonium sulfate are used, the increase of TreA activity is correlated with
a conformational change of the protein or dimerization. The substrate
specificity of the purified enzyme was characterized, showing additionally
that trehalose is also hydrolyzed, but to a much smaller extent than
trehalose-6-phosphate. In vitro, the presence of glucose reduces TreA
activity, indicating product inhibition of the enzyme.
Copyright © 1995, American Society for Microbiology
Purification and characterization of the phospho-alpha(1,1)glucosidase (TreA) of Bacillus subtilis 168
Lehrstuhl fur Mikrobiologie, Friedrich-Alexander Universitat Erlangen- Nurnberg, Federal Republic of Germany.
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