Purification and characterization of the first reptile pancreatic lipase - The turtle

Objectives: The aim of the present study was to purify and characterize classic pancreatic lipase from the reptile turtle (TuPL). Methods: The lipase was purified from the fresh pancreas extract followed by diethylamino ethyl-cellulose chromatography, Sephacryl S-200 gel filtration, and a Mono-Q Sepharose chromatography. Results: Turtle pancreatic lipase is a serine enzyme and it contains only 1 free cysteine. Its activity is maximum at pH 8.2 and 37 degrees C. A specific activity of 10.000 U/mg and 5.000 U/mg were measured titrimetrically on tributyrin and olive oil emulsion, respectively. Natural detergents act as potent inhibitors of TuPL, and colipase restores the activity. When the lipase is inhibited by synthetic detergent, simultaneous addition of colipase and bile salts is required to restore the TuPL activity. The critical surface pressure of TuPL (pi(c) = 20.9 mN m(-1)) is similar to the one of human PL (pi(c) = 18 mN m(-1)). Conclusions: The results presented in this article indicate that despite the primitive character of the turtle, no significant difference has been observed between TuPL and known mammalian PLs. However, partial proteolysis of TuPL with chymotrypsin shows the absence of the 14-kDa fragment identified as the C-terminal domain in the case of many classic PLs.