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Full-Text Articles in Physical Sciences and Mathematics
The Ancestral Activation Promiscuity Of Adp-Glucose Pyrophosphorylases From Oxygenic Photosynthetic Organisms, Misty L. Kuhn, Carlos M. Figueroa, Alberto A. Iglesias, Miguel Ballicora
The Ancestral Activation Promiscuity Of Adp-Glucose Pyrophosphorylases From Oxygenic Photosynthetic Organisms, Misty L. Kuhn, Carlos M. Figueroa, Alberto A. Iglesias, Miguel Ballicora
Miguel A Ballicora
Background ADP-glucose pyrophosphorylase (ADP-Glc PPase) catalyzes the first committed step in the synthesis of glycogen in bacteria and starch in algae and plants. In oxygenic photosynthetic organisms, ADP-Glc PPase is mainly activated by 3-phosphoglycerate (3-PGA) and to a lesser extent by other metabolites. In this work, we analyzed the activation promiscuity of ADP-Glc PPase subunits from the cyanobacterium Anabaena PCC 7120, the green alga Ostreococcus tauri, and potato (Solanum tuberosum) tuber by comparing a specificity constant for 3-PGA, fructose-1,6-bisphosphate (FBP), fructose-6-phosphate, and glucose-6-phosphate. Results The 3-PGA specificity constant for the enzymes from Anabaena (homotetramer), O. tauri, and potato tuber was …
Investigating The Electrostatic Role Of A Critical Arginine For The Catalysis Of E. Coli Adp-Glucose Pyrophosphorylase, Angela Mahaffey, Saleh Aiyash, Miguel Ballicora, Ligin Solamen
Investigating The Electrostatic Role Of A Critical Arginine For The Catalysis Of E. Coli Adp-Glucose Pyrophosphorylase, Angela Mahaffey, Saleh Aiyash, Miguel Ballicora, Ligin Solamen
Miguel A Ballicora
ADP-glucose pyrophosphorylase (ADP-Glc PPase) is the regulatory enzyme of the pathway for starch synthesis in plants and glycogen in mammals and enteric bacteria. It exists as a 200 kDa homotetramer (α4) in enteric bacteria, and as a heterotetramer (α2β2) in plants. In both in vivo and in vitro the substrates (Glucose 1-Phosphate; Glc-1P and Adenosine 5'-Triphosphate; ATP) are converted into a glucose donor ADP-Glucose and a pyrophosphate (PPi) via the ADP-Glc PPase enzyme. It has been noted that some residues are conserved in homotetrameric bacterial ADP-Glc PPases, but are not in some plant forms. One of them is Arginine-32 (R32) …