Figure 3.

Zymogram analysis of glycogen/starch synthase activities from the wild type (WT) and 187G11 mutants. Total protein of semipurified crude extracts of both wild-type and 187G11 mutant strains were separated by native PAGE and then electrotransferred onto native PAGE gels containing 0.6% (p/v) glycogen. The native gels were then incubated with or without 3 mm ADP-Glc. Glycogen/starch synthase activities are seen after iodine staining in the wild type’s crude extract as two dark activity bands (arrows at left). The fast-migrating form disappears in the 187G11 mutant (arrow at right). The total decrease in iodine staining was estimated through dilution to be between 2 to 3 orders of magnitude. This decrease is in line with that measured by quantitative radioactive assays in recombinant E. coli extracts.