Biochemical and molecular characterization of RcSUS1, a cytosolic sucrose synthase phosphorylated in vivo at serine 11 in developing castor oil seeds.

ABSTRACT: Sucrose synthase (SUS) catalyzes the UDP-dependent cleavage of sucrose into UDP-glucose and fructose and has become an important target for improving seed crops via metabolic engineering. A UDP-specific SUS homotetramer composed of 93-kDa subunits was purified to homogeneity from the triacylglyceride-rich endosperm of developing castor oil seeds (COS) and identified as RcSUS1 by mass spectrometry. RcSUS1 transcripts peaked during early development, whereas levels of SUS activity and immunoreactive 93-kDa SUS polypeptides maximized during mid-development, becoming undetectable in fully mature COS. The cytosolic location of the enzyme was established following transient expression of RcSUS1-enhanced YFP in tobacco suspension cells and fluorescence microscopy. Immunological studies using anti

SUBMITTER: Fedosejevs ET 

PROVIDER: S-EPMC4246097 | biostudies-literature | 2014 Nov

REPOSITORIES: biostudies-literature