The heteromultimeric debranching enzyme involved in starch synthesis in Arabidopsis requires both isoamylase1 and isoamylase2 subunits for complex stability and activity.

ABSTRACT: Isoamylase-type debranching enzymes (ISAs) play an important role in determining starch structure. Amylopectin - a branched polymer of glucose - is the major component of starch granules and its architecture underlies the semi-crystalline nature of starch. Mutants of several species lacking the ISA1-subclass of isoamylase are impaired in amylopectin synthesis. Consequently, starch levels are decreased and an aberrant soluble glucan (phytoglycogen) with altered branch lengths and branching pattern accumulates. Here we use TAP (tandem affinity purification) tagging to provide direct evidence in Arabidopsis that ISA1 interacts with its homolog ISA2. No evidence for interaction with other starch biosynthetic enzymes was found. Analysis of the single mutants shows that each protein is destabili

SUBMITTER: Sundberg M 

PROVIDER: S-EPMC3787081 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature