Inhibition of chaperonin ATPase activity by various co-chaperonins.

Steady-state ATPase activity was measured for each chaperonin. The T.O.N values (1/min) were 3.27±0.32, 0.83±0.14, 0.91±0.1 and 0.79±0.08 for GroEL, mHsp60, E321K and R264K/E358K, respectively. The percentage of ATPase inhibition by each co-chaperonin is indicated. The experiment was carried out using a 2∶1 molar ratio of co-chaperonin:chaperonin. Plus (+) and minus (−) indicate the ability and inability, respectively, of each chaperonin-co-chaperonin pair to mediate the refolding of HCl-denaturated MDH (as depicted in Fig. 5).