Comparison of the α-Amylase of Bacillus subtilis and Bacillus amyloliquefaciens

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Abstract
The α-amylase (α-1,4-glucan 4-glucanohydrolase, EC 3.2.1.1) of Bacillus subtilis strain W23 is less negatively-charged than the α-amylase of B. amyloliquefaciens strain F, as determined by electrophoretic mobility in polyacrylamide gel at pH 8.6. The α-amylase of strain W23 is immunologically unrelated to the α-amylase of strain F, as judged by lack of cross-reaction in Ouchterlony immunodiffusion studies. The pH range of maximal activity for the enzyme of strain W23 was 5.7 to 6.7, with a maximum at 6.3. The pH range of activity for the α-amylase of strain F was 5.5 to 6.5, with a maximum at 5.9. No significant difference was found in the effect of temperature on the activity of the α-amylase of strain W23 and strain F. α-Amylase production by strain W23 occurs throughout the 7-hr growth period, whereas enzyme production by strain F does not begin until the culture enters the stationary phase of growth. The total amounts of enzyme produced by strains W23 and F after 7 hr of growth were 0.3 and 25.5 units/ml, respectively.