1999 Volume 46 Issue 4 Pages 453-457
The branch formations on starches from rice, potato, sweet potato, wheat, corn, sago, and tapioca using rice branching enzyme 1 (RBEI) were examined by high-performance anion exchange chromatography with a pulsed amperometric detector (HPAEC-PAD) after debranching with isoamylase. Irrespective of the difference of the structures of substrate starches, RBEI changed them to an almost similar structure with the two peaks at degrees of polymerization (DP) of 6 and 10 to 11 glucose chains. The longer chain transformation was saturated by 10-h incubation, while DP 6-glucose chain transformation was not saturated after 22-h incubation. When the structure of the substrate starch was not well branched, both DP 6-glucose chains and longer chains were well transferred by RBEI, but when the substrate was already well branched, the transfer reactions of longer chains decreased. The branching reaction seemed to be limited by the density of the glucose chains regardless of the structures of the original starches.