Carbohydrates

Regulation of Carbohydrate Metabolism

The regulation of carbohydrate metabolism is critical to growth and development of plants, and to the yield of major products such as starch and sucrose. The aim of the project is to identify and characterize key elements of regulatory mechanisms which determine the flow of carbon and nutrients in plants. Hereby, we will provide a basis for a better understanding of the integrated source-sink system in important crop plants.

 

We seek to understand the regulation of selected enzyme activities, which are responsible for mediating hexose metabolism in the cytosol of the cells. Fructose-2,6-bisphosphate (Fru-2,6-bisP) is a signal compound, which modifies the activity of specific enzymes in all eukaryotic organisms. These enzymes mediate the metabolism of hexose-phosphates, and in plants Fru.2,6-bisP are therefore important carbon flux and to biosynthesis major carbohydrates, including sucrose and starch.

 

Fru-2,6-bisP is both formed and degraded by a specific bifunctional enzyme (Fru-6-P,2-kinase/ Fru-2,6-BPase). We characterize the kinetic and molecular properties the plant enzyme (termed F2KP), and we determine the role in metabolic regulation.

 

The plant enzyme consists of three regions: The phosphatase region in the C-terminus, the kinase region, and an N-terminus region, which is about 345 amino acids long and which is unique to the plant enzymes.

We are presently focusing our research on:

• Molecular analysis of the function of the N-terminal region of F2KP.

• Characterization of growth and metabolism of knock-out mutants which can not form any Fru-2,6-bisP.

• Characterization of plants with new versions of F2KP, which have been engineered to serve as tools for studying the molecular interactions with other cellular components.

This research relies on expression of active recombinant version of the enzyme in both plants and microorganisms, and on isolation of T-tagged knock-out mutants of Arabidopsis.

 

The persons currently working at the project:

 

Tom Hamborg Nielsen, Associate Professor, E-mail:
Lena Nilsson, post doc. 
Helle Mogensen, Technician, E-mail:
Chloe, Meier, Technician trainee, E-mail: