Action pattern and specificity of an amylase from Bacillus subtilis

Abstract

The nature, amounts, and sequence of products formed from well-characterized substrates by the action of a crystalline α-type amylase from Bacillus subtilis were determined by qualitative and quantitative paper chromatography. The substrates studied were amylose, amylopectin, glycogen, β-amylase limit dextrins, pure individual maltodextrins, and the cyclic Schardinger dextrins. The amylase from B. subtilis showed a dual product specificity for the formation of maltotriose and maltohexaose. This dual specificity was quite pronounced when amylopectin was the substrate. The distributions of products from the interior segments of amylopectin and glycogen were completely different from the distribution of products obtained from amylose. The reactions of the maltodextrins were highly specific and dependent upon the molecular size of the dextrin. From these studies, a mechanism for the dual product specificity and action on branched substrates is proposed.