Stran 1 iz 21 rezultatov
A combined DSC-SAXS approach was employed to study the effects of amylose and phosphate esters on the assembly structures of amylopectin in B-type polymorphic potato tuber starches. Amylose and phosphate levels in the starches were specifically engineered by antisense suppression of the granule
The potato tuber (Solanum tuberosum) GWD (alpha-glucan, water dikinase) catalyses the phosphorylation of starch by a dikinase-type reaction mechanism in which the beta-phosphate of ATP is transferred to the glucosyl residue of amylopectin. GWD shows sequence similarity to bacterial pyruvate, water
Cold-induced sweetening (CIS) caused by reducing sugar (RS) accumulation during storage in low temperature in potato tubers is a critical factor influencing the quality of fried potato products. The reconditioning (REC) by arising storage temperature is a common measure to lower down RS. However,
Brassinosteroids (BRs), a new class of steroid hormones, are involved in the regulation of plant cell elongation and seed germination. Nevertheless, the molecular mechanism of the effect of BRs on tuber sprouting remains largely unknown. In this study, quantitative phosphoproteomics was employed to
The plant genome encodes at least two distinct and evolutionary conserved plastidial starch-related dikinases that phosphorylate a low percentage of glucosyl residues at the starch granule surface. Esterification of starch favours the transition of highly ordered α-glucans to a less ordered state
Starch phosphorylation is an important aspect of plant metabolism due to its role in starch degradation. Moreover, the degree of phosphorylation of starch determines its physicochemical properties and is therefore relevant for industrial uses of starch. Currently, starch is chemically phosphorylated
The recently discovered potato tuber (Solanum tuberosum) alpha-glucan, water dikinase (GWD) (formerly known as R1) catalyzes the phosphorylation of starch by a dikinase-type reaction mechanism in which the beta-phosphate of ATP is transferred to either the C-6 or the C-3 position of the glucosyl
Starch is of fundamental importance for plant development and reproduction and its optimized molecular assembly is potentially necessary for correct starch metabolism. Re-structuring of starch granules in-planta can therefore potentially affect plant metabolism. Modulation of granule micro-structure
The molecular deposition of starch extracted from normal plants and transgenically modified potato lines was investigated using a combination of light microscopy, environmental scanning electron microscopy (ESEM) and confocal laser scanning microscopy (CLSM). ESEM permitted the detailed (10 nm)
Phosphate groups are naturally present in starch at C3- or C6-position of the glucose residues and impact the structure of starch granules. Their precise quantification is necessary for understanding starch physicochemical properties and metabolism. Nevertheless, reliable quantification of Glc-3-P
BACKGROUND
Native starch accumulates as granules containing two glucose polymers: amylose and amylopectin. Phosphate (0.2-0.5%) and proteins (0.1-0.7%) are also present in some starches. Phosphate groups play a major role in starch metabolism while granule-bound starch synthase 1 (GBSS1) which
Starches extracted from most plant species are phosphorylated. alpha-Glucan water dikinase (GWD) is a key enzyme that controls the phosphate content of starch. In the absence of its activity starch degradation is impaired, leading to a starch excess phenotype in Arabidopsis and in potato leaves, and
The phosphorylation of the amylopectin fraction of starch catalyzed by the alpha-glucan, water dikinase (GWD, EC 2.7.9.4) plays a pivotal role in starch metabolism. Limited proteolysis of the potato tuber (Solanum tuberosum) GWD (StGWD, 155 kDa) by trypsin primarily produced stable fragments of 33
For quantification of alpha-glucan, water dikinase (GWD) activity in crude extracts of plant tissues a radio-labeling assay was established that uses soluble starch and (33)P-labeled ATP as phosphate acceptor and donor, respectively. A constant rate of starch labeling was observed only if the ATP
Starch phosphorylation catalysed by the alpha-glucan, water dikinases (GWD) has profound effects on starch degradation in plants. The Arabidopsis thaliana genome encodes three isoforms of GWD, two of which are localized in the chloroplast and are involved in the degradation of transient starch. The