title: Starch phosphorylation: insights and perspectives.
abstract: During starch metabolism, the phosphorylation of glucosyl residues of starch, to be more precise of amylopectin, is a repeatedly observed process. This phosphorylation is mediated by dikinases, the glucan, water dikinase (GWD) and the phosphoglucan, water dikinase (PWD). The starch-related dikinases utilize ATP as dual phosphate donor transferring the terminal γ-phosphate group to water and the β-phosphate group selectively to either C6 position or C3 position of a glucosyl residue within amylopectin. By the collaborative action of both enzymes, the initiation of a transition of α-glucans from highly ordered, water-insoluble state to a less order state is realized and thus the initial process of starch degradation. Consequently, mutants lacking either GWD or PWD reveal a starch excess phenotype as well as growth retardation. In this review, we focus on the increased knowledge collected over the last years related to enzymatic properties, the precise definition of the substrates, the physiological implications, and discuss ongoing questions.
authors.affiliation: Biopolymer Analytics, University of Potsdam, Karl-Liebknecht 24-25, 14476, Potsdam-Golm, Germany.|Institute of General Botany, Friedrich Schiller University Jena, Am Planetarium 1, 07743, Jena, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Mahlow
authors.affiliation: Biopolymer Analytics, University of Potsdam, Karl-Liebknecht 24-25, 14476, Potsdam-Golm, Germany.|Department of Biochemistry, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159, 02-776, Warsaw, Poland.
authors.forename: Sławomir
authors.initials: S
authors.lastname: Orzechowski
authors.affiliation: Biopolymer Analytics, University of Potsdam, Karl-Liebknecht 24-25, 14476, Potsdam-Golm, Germany. fettke@uni-potsdam.de.|Department of Biochemistry, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159, 02-776, Warsaw, Poland. fettke@uni-potsdam.de.
authors.forename: Joerg
authors.initials: J
authors.lastname: Fettke
mesh_terms: D017360:Arabidopsis / Q000378:metabolism; D010641:Phenotype; D010710:Phosphates / Q000378:metabolism; D010766:Phosphorylation; D013213:Starch / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D010710:Phosphates; D013213:Starch
keywords: Glucan, water dikinase; Phosphoglucan, water dikinase; Starch degradation; Starch metabolism; Starch phosphorylation