The enzyme activity of MDH was measured in absence and presence of 30 μM HSP18 preincubated with/without (A) 0.01–3 mM ATP; (B) 1 mM ATP/ATP-γS during its thermal denaturation at 43°C. The assay also performed with 30 μM BSA alone or preincubated with 0.01–3 mM ATP. ***p<0.0005.