Abstract
The amylopectin, which is the main constitutent of starch granule, is produced by the action of soluble starch synthases(SSS), starch branching enzymes(SBE), and starch debranching enzymes(DBE). Especially, DBEs; isoamylase(ISA) and pullulanase(PUL) play a crucial role in formation of multiple cluster structure of amylopectin molecule.
It is known there are three kinds of ISA genes in Maize and Potato. So, we tried to isolate the ISA3 homolog of Barley (HvISO3), in addition to HvISO1 and HvISO2 that were already identified as ISA genes in Barley. The RACE method was used to isolate the putative HvISO3 of Barley. Northern blot analysis showed that the HvISO3 expression was high-level in green tissues especially young leaves, but it was low-level in embryo and endosperm. Therefore, it was suggested that the HvISO3 has a different function from other two HvISO genes. We will discuss the relevance of three HvISO genes and their subunits.
