De Santi_2012_Biotechnol.Prog_28_946

Cold-adapted enzymes possess high specific activity at low and moderate temperatures with respect to their mesophilic and thermophilic homologs it is accepted that they have a less rigid and more flexible structure in the region surrounding the active site However the low stability of such molecules could represent the main barrier for their application in some industrial bioprocesses The aim of this article was to investigate the ability of the naturally occurring osmolytes to increase the thermal stability and the specific activity of the cold-active lipase from Psychrobacter sp TA144 PsyHSL which belongs to the hormone-sensitive lipase group The effect of trimethylamine N-oxide TMAO betaine and L-proline addition on the activity and thermal stability of PsyHSL was investigated by means of biochemical and biophysical techniques It turned out that in the presence of 3 M TMAO the enzyme specific activity enhanced up to 250 at 50 degrees C while the addition of 1 M TMAO increased the thermostability fivefold at 45 degrees C Our experiments demonstrated that even in the case of a psychrophilic enzyme osmoprotectants particularly TMAO addition may be considered an efficient strategy to improve the protein thermal stability and specific activity at higher temperatures.