Activity and action pattern of Bacillus licheniformis α‐amylase in aqueous ethanol

摘要

>A purified B. licheniformis α-amylase in a mixture of ethanol-aqueous buffer (1:1, data-equation-construct="true" class="math-equation-construct"> data-equation-image="true" class="math-equation-image"> alt="math formula" src="http://onlinelibrary.wiley.com/store/10.1016/0014-5793(85)80714-6/asset/equation/feb20014579385807146-math-si1.gif?v=1&s=a7d5af4437a1364868ad898f69013f83b58ea115" class="inlineGraphic" /> data-equation-mathml="true" class="math-equation-mathml" style="display:none">) retains half the activity shown in water alone. In ethanol-aqueous buffer (7:3, data-equation-construct="true" class="math-equation-construct"> data-equation-image="true" class="math-equation-image"> alt="math formula" src="http://onlinelibrary.wiley.com/store/10.1016/0014-5793(85)80714-6/asset/equation/feb20014579385807146-math-si2.gif?v=1&s=76b438ba945dbefea942d526efef5dae8912889e" class="inlineGraphic" /> data-equation-mathml="true" class="math-equation-mathml" style="display:none">) 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 ethanolaqueous buffer (7:3, data-equation-construct="true" class="math-equation-construct"> data-equation-image="true" class="math-equation-image"> alt="math formula" src="http://onlinelibrary.wiley.com/store/10.1016/0014-5793(85)80714-6/asset/equation/feb20014579385807146-math-si3.gif?v=1&s=06a1f9eb21a16765a6b553ed3451bd83336a3de6" class="inlineGraphic" /> data-equation-mathml="true" class="math-equation-mathml" style="display:none">) 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 ethanolaqueous buffer medium.