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Interaction between D-glyceraldehyde-3-phosphate dehydrogenase and calmodulin
T Y Christova1, F Orosz, J Ovádi
1Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, Budapest, Hungary.
Biochemical and Biophysical Research Communications
|November 12, 1996
Summary
Calmodulin binds to glyceraldehyde-3-phosphate dehydrogenase, altering its structure without affecting catalytic activity. This interaction, modulated by drugs and aldolase, may influence protein associations within the cell.
Area of Science:
- Biochemistry
- Molecular Biology
- Enzymology
Background:
- Calmodulin is a key calcium-binding protein involved in cellular signaling.
- D-glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a crucial enzyme in glycolysis and also has moonlighting functions.
Purpose of the Study:
- To investigate the effect of calmodulin on the associative properties of D-glyceraldehyde-3-phosphate dehydrogenase (GAPDH).
- To characterize the binding interaction between calmodulin and GAPDH.
Main Methods:
- Utilized a covalently attached fluorescent probe to monitor changes in GAPDH.
- Investigated the binding affinity using apparent dissociation constant measurements.
- Assessed the impact of calmodulin on enzyme activity and complex formation.
Main Results:
- Calmodulin shifts the equilibrium between different forms of GAPDH.
- Calmodulin binds to GAPDH subunits with an apparent dissociation constant of 1.8 microM.
- Calmodulin binding does not alter the catalytic activity of GAPDH.
- Trifluoperazine and aldolase modulate the formation of the calmodulin-GAPDH complex.
Conclusions:
- Calmodulin interacts with GAPDH, influencing its quaternary structure.
- The calmodulin-GAPDH complex formation is regulated by specific drugs and other proteins.
- These associations may play a role in mediating interactions with other cellular components.