Allosteric regulation in Acetohydroxyacid Synthases (AHASs)--different structures and kinetic behavior in isozymes in the same organisms.

@article{Barak2012AllostericRI,
  title={Allosteric regulation in Acetohydroxyacid Synthases (AHASs)--different structures and kinetic behavior in isozymes in the same organisms.},
  author={Ze'ev Barak and David M. Chipman},
  journal={Archives of biochemistry and biophysics},
  year={2012},
  volume={519 2},
  pages={167-74}
}
Acetohydroxyacid Synthases (AHASs) have separate small regulatory subunits which specifically activate the catalytic subunits with which they are associated. The binding sites for the inhibitory amino acid(s) (valine or leucine) are in the interface between two ACT (small ligand binding) domains, and are apparently found in all AHAS regulatory subunits. However, the structures and the kinetic mechanisms of the different enzymes are very heterogeneous. Among the three isozymes encoded in the… CONTINUE READING