alpha glucan/potato

alpha-Glucan phosphorylases degrade linear or branched oligosaccharides via a glycosyl transfer reaction, occurring with retention of configuration, to generate alpha-glucose-1-phosphate (G1P). We report here the chemoenzymic synthesis of two incompetent oligosaccharide substrate analogues,

The affinity of potato tuber starch-branching enzyme-I (PSBE-I) for various linear malto-oligosaccharides, cyclodextrins, (CDs) and macromolecular alpha-glucans was investigated by alpha-glucan induced fluorescence quenching of intrinsic PSBE-I tryptophan residues and by affinity electrophoresis.

The thermostability of potato type L alpha-glucan phosphorylase (EC 2.4.1.1) was enhanced by random and site-directed mutagenesis. We obtained three single-residue mutations-Phe39-->Leu (F39L), Asn135-->Ser (N135S), and Thr706-->Ile (T706I)-by random mutagenesis. Although the wild-type enzyme was

The Michaelis-Menten parameters (Vmax and Km) for turnover of an extensive series of deoxy and deoxyfluoro derivatives of alpha-D-glucopyranosyl phosphate by the alpha-glucan phosphorylase from potato tuber have been determined. Very large rate reductions are observed as a consequence of each

Alpha-Glucan phosphorylase (EC 2.4.1.1.) was purified from sweet potato roots. Apparently homogeneous preparations obtained are partially degraded products from phosphorylase, as judged from the results of molecular weight determination, NH-2-termini analysis and pyridoxal-5'-P assay. Phosphorylase

Photooxidation of alpha-glucan phosphorylases from rabbit muscle and potato tubers in the presence of rose bengal leads to a rapid loss of enzymatic activity which follows first-order kinetics. The process is pH dependent, being more rapid at higher pH. The inactivation is closely related to the

We describe the successful heterologous expression of the Solanum tuberosum alpha-glucan phosphorylase (GP) gene in Aspergillus niger. Special attention was paid to the influence of different codon usage and A+T content in the coding region on GP protein expression. Use of A. niger-preferred codon

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

A potato starch synthase III (PSSIII) was expressed in the Synechocystis mutants deficient in either glycogen synthase I (M1) or II (M2) to replenish α-(1,4) linkage synthesizing activity, resulting in new mutants, PM1 and PM2, respectively. These mutants were applied to study the role of exogenous

The complete amino acid sequence of potato alpha-glucan phosphorylase has been determined. The monomer contains 916 amino acids with a molecular weight of 103,916. About one-fourth of the amino-terminal threonine is blocked by an acetyl group. Sequence comparison among phosphorylases from potato

The type L isozyme of potato tuber alpha-glucan phosphorylase [EC 2.4.1.1], a dimer of 104-kDa subunits, is compartmentalized in the amyloplast. We have cloned a nearly full-length cDNA encoding this isozyme from a cDNA library of immature potato tuber. The sequence was supplemented by a partial

The action of phosphorylase b from rabbit muscle and potato phosphorylase was inhibited to various extents by several glucose analogs. Like glucose itself, all of the glucosidic oxygen-substituted analogs tested in kinetic experiments showed a nonlinear competitive inhibition for muscle