We have conducted solution small-angle scattering experiments on the bovine heat shock cognate protein (Hsc70) and fragments thereof, including the ATPase fragment, the peptide binding fragment, full-length protein and a "60 kDa" fragment that has approximately 100 amino acids deleted from carboxy terminus. From steady-state measurements, we find that Hsc70 is an elongated protein. Kinetic measurements show the ATP-induced decrease to be rapid, relative to the rate of ATP hydrolysis; it occurs in less than a minute, while the time constant for hydrolysis is ~5 minutes. The transition to the ATP-induced state therefore results from ATP binding, not from ATP hydrolysis. A manuscript from these results is currently in preparation.