Lappuse 1 no 156 rezultātiem
The goal of our work was a role of phosphorylase (EC. 2.4.1.1) in starch accumulation in plastids of storage parenchyma cells in potato minitubers forming under clinorotation. An increased enzyme activity under the influence of simulated microgravity has been revealed by using the biochemical and
On-line size-exclusion chromatography monitoring of potato phosphorylase catalyzed amylose synthesis--starting from alpha-D-glucose-1-P and maltohexaose--revealed rather monodisperse amylose populations. In the presence of lipids, amylose-lipid complexes spontaneously formed and precipitated. They
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,
P1,P2-bis(5'-pyridoxal)diphosphate crosslinks between the original cofactor (pyridoxal 5'-phosphate) linking residue and Lys-573 in rabbit muscle phosphorylase (Shimomura, S., Nakano, K., & Fukui, T. (1978) Biochem. Biophys. Res. Commun. 82, 462-468). We have applied the same technique to potato
Phosphorylases (EC 2.4.1.1) from potato and rabbit muscle are similar in many of their structural and kinetic properties, despite differences in regulation of their enzyme activity. Rabbit muscle phosphorylase is subject to both allosteric and covalent controls, while potato phosphorylase is an
Analysis of the levels of starch phosphorylase mRNA and its product in the various organs of the potato plant indicates that the gene is differentially regulated, leading to a high accumulation of the gene product in tubers. The amount of phosphorylase transcripts synthesized in nuclei isolated from
In potato tubers two starch phosphorylase isozymes, types L and H, have been described and are believed to be responsible for the complete starch breakdown in this tissue. Type L has been localized in amyloplasts, whereas type H is located within the cytosol. In order to investigate whether the same
The amino acid sequence around the pyridoxal 5'-phosphate binding site in potato phosphorylase was determined in order to compare it with those in phosphorylases from other sources having different regulatory properties. The potato enzyme was reduced by NaBH4 in the presence of urea,
Amino acid sequence analysis of the cyanogen bromide peptides of potato alpha-glucan phosphorylase was undertaken for comparison with rabbit muscle glycogen phosphorylase and for elucidation of the structural bases for the differences in the catalytic and regulatory properties between the animal and
Aspergillus oryzae alpha-amylase [(1----4)-alpha-D-glucan glucanohydrolase, EC 3.2.1.1] produced O-(6-phosphoryl-alpha-D-glucopyranosyl)-(1----4)-O-alpha-D-glucopyran osy l-(1----4)-D-glucopyranose (6(3)-phosphorylmaltotriose) and
alpha-D-Glucopyranose-1.2-cyclic phosphate is a potent inhibitor of potato starch phosphorylase-catalyzed (1,4-alpha-D-glucan:orthophosphate alpha-glucosyltransferase, EC 2.4.1.1) starch elongation. The inhibition is competitive with respect to alpha-D-glucopyranose 1-phosphate (Glc-1-P) with Ki
Starch phosphorylase has been cloned from a lambda gt10 cDNA library of potato tuber mRNA. Selected recombinants have been used to demonstrate that phosphorylase mRNA is most abundant in tubers but is also detectable in stolon, root, stem and leaf tissue. The level of phosphorylase mRNA was greatly
Phosphorylase was purified from young and senescent potato tubers. Antibodies raised against the enzyme from young tubers crossreacted with phosphorylase from old tissue, although the latter exhibited different physico-chemical properties. In polyacrylamide gel electrophoresis it migrated with
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
Higher plant tissues contain two alpha-glucan phosphorylase isozymes (EC 2.4.1.1), types L and H, localized in the plastid and the cytoplasm, respectively. We already isolated and sequenced a cDNA clone encoding the type L isozyme. Presently, a cDNA clone encoding the type H counterpart was isolated