Activity and action pattern of Bacillus licheniformis alpha-amylase in aqueous ethanol.
A purified B. licheniformis alpha-amylase in a mixture of ethanol-aqueous buffer (1:1, v/v) retains half the activity shown in water alone. In ethanol-aqueous buffer (7:3, v/v) about 20% of the activity is retained. The pattern of oligosaccharides produced from amylose changed with ethanol concentration; in aqueous buffer the products are: DP 1 and 2, 33.7%; DP 3, 28.5%; DP 4, 4.4% and DP 5, 33.4%. Whereas in ethanol-aqueous buffer (7:3, v/v) the products are DP 1 and 2, 66.8%; DP 3, 17.3%; DP 4, 4.1% and DP 5, 11.8%. These results suggest that a change in substrate affinity at the active centre subsites is induced in the ethanol-aqueous buffer medium.
D001407:Bacillus / Q000201:enzymology*; D003124:Colorimetry / Q000379:methods; D004789:Enzyme Activation; D000431:Ethanol / Q000494:pharmacology*; D007700:Kinetics; D000516:alpha-Amylases / Q000378:metabolism*
D000431:Ethanol; D000516:alpha-Amylases