Study on Outer Chains Released from Amylopectin between Immobilized and Free Debranching Enzymes.

Abstract

Various kinds of partial hydrolysates of waxy maize amylopectin were prepared by controlling the debranching actions of immobilized and free isoamylase, and free pullulanase, and then frac tionated into three fractions by a gel chromatography using Toyopearl HW-65F . The smallest frac tions (fr. 3) were again debranched with free isoamylase and analyzed by HPAEC-PAD in order to obtain information of chain distributions existing in the outer portion of amylopectin molecules. About 10-15% of the partial hydrolyses were appropriate to collect the shortish chains released from amylopectin. The chain distribution of the smallest fraction consisted of many short-chains with DP 6-15, and it could be thought that most of the shortish chains might be A chains derived from outer portions of amylopectin. The comparative experiments among the debranching enzymes led us to confirm that partial hydrolyzed materials obtained by the low enzyme activity of free isoamylase and pullulanase could be used to study the outer chains of amylopectins like immobilized isoamylase.