... 8.5, we studied thermal stability of 17b-HSDcl from CD and UV meltingcurves, from which the temperature of denaturation(Td) and the van’t Hoff enthalpy of denaturation(DH°vH )of1 7b-HSDcl were ... pH > 10. Of note, the observed thermody-namic stability of 17b-HSDcl at 25 °C, with a value of 15.3 kJÆmol)1(0.06 kJÆmol)1amino acid), is muchlower than for the majority of globular ... concentrations of 1.2and 0.4 m, respectively. Binding of the coenzyme NADPH to 17b-HSDclcauses local structural changes that do not significantly affect the thermal stability of this protein.AbbreviationsCd,...