Journal article
The potato tuber, maize endosperm and a chimeric maize-potato ADP-glucose pyrophosphorylase exhibit fundamental differences in Pi inhibition
Archives of biochemistry and biophysics, Vol.537(2), pp.210-216
09/15/2013
Handle:
https://hdl.handle.net/2376/105575
PMID: 23906662
Abstract
•ADP-glucose pyrophosphorylase is a highly regulated enzyme.•Key regulators in plant enzymes are 3-phosphoglyceric acid and inorganic phosphate.•Enzyme forms respond differently to 3-phosphoglyceric acid and inorganic phosphate.•Pi inhibition data suggest maize AGPase has one effector site that binds 3-PGA and Pi.•Other enzymes exhibit complex behavior having at least two separate sites for Pi.
ADP-glucose pyrophosphorylase (AGPase) is highly regulated by allosteric effectors acting both positively and negatively. Enzymes from various sources differ, however, in the mechanism of allosteric regulation. Here, we determined how the effector, inorganic phosphate (Pi), functions in the presence and absence of saturating amounts of the activator, 3-phosphoglyceric acid (3-PGA). This regulation was examined in the maize endosperm enzyme, the oxidized and reduced forms of the potato tuber enzyme as well as a small subunit chimeric AGPase (MP), which contains both maize endosperm and potato tuber sequences paired with a wild-type maize large subunit. These data, combined with our previous kinetic studies of these enzymes led to a model of Pi inhibition for the various enzymes. The Pi inhibition data suggest that while the maize enzyme contains a single effector site that binds both 3-PGA and Pi, the other enzymes exhibit more complex behavior and most likely have at least two separate interacting binding sites for Pi. The possible physiological implications of the differences in Pi inhibition distinguishing the maize endosperm and potato tuber AGPases are discussed.
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Details
- Title
- The potato tuber, maize endosperm and a chimeric maize-potato ADP-glucose pyrophosphorylase exhibit fundamental differences in Pi inhibition
- Creators
- Susan K Boehlein - Program in Plant Molecular and Cellular Biology and Horticultural Sciences, University of Florida, 1253 Fifield Hall, Gainesville, FL 32611, USAJanine R Shaw - Program in Plant Molecular and Cellular Biology and Horticultural Sciences, University of Florida, 1253 Fifield Hall, Gainesville, FL 32611, USADonald R McCarty - Program in Plant Molecular and Cellular Biology and Horticultural Sciences, University of Florida, 1253 Fifield Hall, Gainesville, FL 32611, USASeon-Kap Hwang - Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USAJon D Stewart - Department of Chemistry, University of Florida, 127 Chemistry Research Building, Gainesville, FL 32611, USAL. Curtis Hannah - Program in Plant Molecular and Cellular Biology and Horticultural Sciences, University of Florida, 1253 Fifield Hall, Gainesville, FL 32611, USA
- Publication Details
- Archives of biochemistry and biophysics, Vol.537(2), pp.210-216
- Academic Unit
- Biological Chemistry, Institute of
- Publisher
- Elsevier Inc
- Identifiers
- 99900546709001842
- Language
- English
- Resource Type
- Journal article