Figure 5

Branching pattern models. A. Branching pattern models for amylopectin from sbe1a and Wt starches. Shown are b-dextrins approaching the limit of digestion by β-amylase, with differences in the amount of DP 4 stubs. All circles indicate glucose units. Dotted line indicates more glucose units. Dotted circles indicate glucose hydrolyzed by β-amylase. Solid black circles indicate branch points. Circles with a slash indicate reducing ends. Circles in an ellipse indicate glucose units that would result in a DP 4 chain. Arrows indicate the action sites of β-amylase. Arrows with a cross indicates that action of β-amylase is prevented by closely associated branch points nearby. Fast and slow indicate the first and second stage of β-amylolysis, respectively. B. Branching pattern models for a region of the amylose from sbe1a and Wt starches. Shown are β-limit dextrins that are consistent with difference in action of isoamylase. All circles indicate glucose units. Dotted lines indicate more glucose units. Solid black circles indicate branch points. Circles with a slash indicate reducing ends. Arrows indicate the action sites of isoamylase. Arrows with a cross indicates that action of isoamylase is prevented by closely associated branch points nearby. The model does not consider the presence of B chains. C. Proposed overall amylose branching pattern models for sbe1a and Wt starches, consistent with the differences in actions of β-amylase and isoamylase. All lines indicate glucose chains. Solid black circles indicate branch points. Circles with a slash indicate reducing ends.