Reversible Cyclic Thermal Inactivation of Oligopeptidase B from Serratia proteamaculans.

A unique property was found for oligopeptidase B from (PSP) as well as its mutants: they can undergo reversible thermal inactivation at 37°C, with activity being restored or even increased with respect to the initial one upon subsequent cooling. The process can be repeated several times, with the same results achieved (up to 5 cycles). This effect can be explained by a shift in the equilibrium between the inactive open form of the enzyme and the active closed one upon variation of the incubation temperature.