The Allosterically Unregulated Isoform of ADP-Glucose Pyrophosphorylase from Barley Endosperm Is the Most Likely Source of ADP-Glucose Incorporated into Endosperm Starch.

@article{Doan1999TheAU,
  title={The Allosterically Unregulated Isoform of ADP-Glucose Pyrophosphorylase from Barley Endosperm Is the Most Likely Source of ADP-Glucose Incorporated into Endosperm Starch.},
  author={Doan and Rudi and Olsen},
  journal={Plant physiology},
  year={1999},
  volume={121 3},
  pages={
          965-975
        }
}
  • Doan, Rudi, Olsen
  • Published 1 November 1999
  • Biology
  • Plant physiology
We present the results of studies of an unmodified version of the recombinant major barley (Hordeum vulgare) endosperm ADP-glucose pyrophoshorylase (AGPase) expressed in insect cells, which corroborate previous data that this isoform of the enzyme acts independently of the allosteric regulators 3-phosphoglycerate and inorganic phosphate. We also present a characterization of the individual subunits expressed separately in insect cells, showing that the SS AGPase is active in the presence of 3… 
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TLDR
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TLDR
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Characterization of the Genes Encoding the Cytosolic and Plastidial Forms of ADP-Glucose Pyrophosphorylase in Wheat Endosperm1
TLDR
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TLDR
The import of ADPG from the cytosol into amyloplasts offers a means of regulating both the flux of carbon to the enzymes of starch synthesis, and the nature of the end product.
The gene encoding the cytosolic small subunit of ADP-glucose pyrophosphorylase in barley endosperm also encodes the major plastidial small subunit in the leaves.
TLDR
The barley (Hordeum vulgare) gene Hv.AGP.S.1 produces two different transcripts encoding small subunits (SSUs) of ADP-glucose pyrophosphorylase (AGPase) that are physiologically relevant and important for starch synthesis in the endosperm and the leaves.
ADP-Glucose Pyrophosphorylase: A Regulatory Enzyme for Plant Starch Synthesis
TLDR
Prediction of the ADPGlc PPase secondary structure suggests that it shares a common folding pattern to other sugar-nucleotide pyrophosphorylases, and they evolved from a common ancestor.
ADP-glucose pyrophosphorylase large subunit 2 is essential for storage substance accumulation and subunit interactions in rice endosperm.
On the Roles of Wheat Endosperm ADP-Glucose Pyrophosphorylase Subunits
TLDR
The unusual insensitivity to activation of the wheat endosperm enzyme is caused by a pre-activation of the L subunit, and the heat stability and sensitivity to phosphate are given by the S subunit.
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The Major Form of ADP-Glucose Pyrophosphorylase in Maize Endosperm Is Extra-Plastidial
TLDR
The finding that the bt2 mutation specifically eliminated the extra-plastidial AGPase activity and the larger of the two proteins recognized by the antibody to the Bt2 subunit are suggested.
Insensitivity of Barley Endosperm ADP-Glucose Pyrophosphorylase to 3-Phosphoglycerate and Orthophosphate Regulation
TLDR
The small, 51-kD subunit of barley endosperm AGP was relatively resistant to proteolysis, both in the presence or absence of protease inhibitors and the relative insensitivity to 3-PGA/Pi regulation has been observed with both the nonproteolyzed crude enzyme and partially purified AGP.
Distinct isoforms of ADPglucose pyrophosphorylase occur inside and outside the amyloplasts in barley endosperm
TLDR
It is suggested that the barley plant contains two distinct isoforms of ADPglucose pyrophosphorylase: one located in plastids (chloroplasts and amyloplasts) and the other in the cytosol of the endosperm, which is probably capable of catalysing the entire flux of carbon to starch.
Brittle-1, an adenylate translocator, facilitates transfer of extraplastidial synthesized ADP--glucose into amyloplasts of maize endosperms.
TLDR
Evidence that in maize endosperms in the linear phase of starch accumulation, 90% or more of the cellular AGPase is extraplastidial is reported, and evidence that the brittle-1 protein (BT1) functions in the transfer of ADP-glucose into the amyloplast stroma.
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TLDR
Analysis of the expression of ADP-glucose synthase at the protein level, using antibodies directed against the Bt2 or Sh2 subunits, established that the variation of activity in the grain was explained by parallel changes in the content of both subunit, and provides an explanation for the earlier reported differences between leaf and grain in the size of peptide and mRNA for the BT2-homologous subunit.
Inhibition of the ADP‐glucose pyrophosphorylase in transgenic potatoes leads to sugar‐storing tubers and influences tuber formation and expression of tuber storage protein genes.
TLDR
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TLDR
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Maize Endosperm ADP–Glucose Pyrophosphorylase SHRUNKEN2 and BRITTLE2 Subunit Interactions
TLDR
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