Comparison of muscle phosphofructokinase from euthermic and hibernating Jaculus orientalis. Purification and determination of the quaternary structure.

1. The structural properties of skeletal muscle phosphofructokinase from euthermic and hibernating jerboa were compared. 2.

Regulation of the skeletal muscle metabolism during hibernation of Jaculus orientalis.

1. The glycolytic flow in the skeletal muscle was considerably depressed during hibernation of Jaculus orientalis. 2.

Conformational modification of muscle phosphofructokinase from Jaculus orientalis upon ligand binding.

Phosphofructokinase from Jaculus orientalis muscle is an allosteric enzyme regulated by substrates and nucleotide effectors. The conformational modifications upon ligand binding were probed by UV difference spectra and reactivities of thiol groups towards dithiobisnitrobenzoate and N-ethylmaleimide. The binding of Fru-6-P induced significant perturbations in the environment of the aromatic residues and buried the most reactive on the three accessible cysteines per protomer.