Mortalin has higher ATPase activity than Hsp70–1A.

<p><b>A</b>) Mortalin (2.50 μmol.L^-1) and Hsp70–1A (2.25 μmol.L^-1) were incubated with ATP (0–2 mmol.L^-1) for 90 min at 37°C, and the Pi released as a result of ATP hydrolysis was quantified. The data were treated through Michaelis-Menten fitting for determination of the kinetic parameters, which are presented in the Figure and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0117170#pone.0117170.t002" target="_blank">Table 2</a>. The results suggested that both mortalin and Hsp70–1A exhibit low ATPase activity. Despite these findings, based on the k_cat value, mortalin presented higher ATPase activity than Hsp70–1A, although the K_M values of both are similar. <b>B</b>) Relative ATPase activity stimulation. Effect of the NR peptide titration on the basal ATPase activity of mortalin and Hsp70–1A at 1 mmol.L^-1 ATP.