Figure 4.

Analysis of GBSSI activity and protein from O. tauri starch granules. A, Coomassie Brilliant Blue R-250 stained 7.5% SDS-acrylamide gels of starch-bound proteins. Lane 1 represents starch-bound proteins extracted from 2 mg of polysaccharides purified after nitrogen starvation. Lane 2 displays the molecular-mass marker with the corresponding masses expressed in kilodaltons. B, Kinetics of in vitro synthesis of amylose. Starch from O. tauri was subjected to in vitro synthesis in the presence of ¹⁴C-labeled ADP-Glc. After 16 h (black line) and 40 h (doted line) of in vitro synthesis, the amylopectin and amylose were separated by CL2B-sepharose chromatography. C, ADP-Glc kinetics of the GBSSI from O. tauri. A total of 100 μg of polysaccharides were incubated with different concentrations of ADP-Glc (▪) or UDP-Glc (○).