Stewart Research GroupDepartment of Chemistry, University of Florida
Understanding a Key Enzyme in Starch Biosynthesis
Stewart Research Group
|
Increasing the starch content of economic
crops such as corn has enormous impact on agriculture's ability to meet
the world's food needs. We are collaborating with a group led by
Curt Hannah (Program in Plant Molecular and Cellular Biology) to
unravel a critical enzyme in the starch biosynthetic pathway. Starch is a branched polymer of glucose synthesized from ADPglucose building blocks. This monomer is assembled from glucose-1-phosphate and ATP by the enzyme ADPglucose pyrophosphorylase. This step is both rate-limiting and the first committed step starch biosynthesis, which makes ADPglucose pyrophosphorylase the key "gatekeeper" enzyme for the pathway.1   The catalytic activity of
the enzyme is influenced by cellular metabolies such as phosphate and
3-phosphoglycerate. We are currently testing the hypothesis that
these two modulators compete for closely linked (or identical) binding
sites on the enzyme. We are also attempting to discover how each
of the four subunits of maize endosperm ADPglucose pyrophosphorylase
contributes to its catalytic ability. These efforts involve
creating and testing the properties of site-directed mutants by kinetic
and binding techniques.2Selected References
|
