EC Number   |
General Information |
Reference |
|---|
   2.7.9.5 | evolution |
the largest differences in the amino acid sequence of GWD, EC 2.7.9.4, and PWD, EC 2.7.9.5, span the non-catalytic N-terminal region. In case of PWD, the N-terminus contains a single starch-binding domain (SBD) that belongs to the well-characterized carbohydrate-binding module (CBM) family CBM20. In contrast to PWD, the identity of the N-terminal starch-binding domain of GWD is less pronounced but might be assigned to the recently identified CBM45 family |
738013 |
| 2.7.9.5 | malfunction |
mutants lacking the enzyme reveal a starch excess phenotype as well as growth retardation. The lack of PWD causes a reduction of G3P alone |
738013 |
| 2.7.9.5 | metabolism |
during starch metabolism, the phosphorylation of glucosyl residues of amylopectin is a repeatedly observed process. The phosphorylation is mediated by dikinases, glucan, water dikinase (GWD, EC 2.7.9.4) and phosphoglucan, water dikinase (PWD, EC 2.7.9.5). By the collaborative action of both enzymes, the initiation of a transition of alpha-glucans from highly ordered, water-insoluble state to a less order state is realized and thus the initial process of starch degradation |
738013 |
| 2.7.9.5 | metabolism |
the enzyme is involved in starch phosphorylation, a key step in starch degradation |
762143 |
| 2.7.9.5 | physiological function |
important enzyme of starch metabolism. Catalyzes the addition of phosphate groups to amylopectin chains at the surface of starch granules, changing its physicochemical properties |
762113 |
| 2.7.9.5 | physiological function |
the starch-related dikinase utilizes ATP as dual phosphate donor transferring the terminal gamma-phosphate group to water selectively to C3 position of a glucosyl residue within amylopectin. The action of the dikinase is restricted to the granule surface and glucan chains exposed at the surface account only for a minor proportion of the entire granule. Glucan chains that are phosphorylated by the dikinase remain covalently linked to the insoluble starch particle. In Arabidopsis leaf starch, about 0.1% of the glucosyl residues are phosphorylated, respectively. PWD is mainly responsible for C3 phosphorylation. A significant PWD-mediated C3 phosphorylation requires the preceding phosphorylation by GWD in Arabidopsis thaiana wild-type starch |
738013 |
