Heterologous expression and functional characterization of sparidae fish digestive phospholipase A 2

Abstract

In this study, we have produced for the first time a fish phospholipase (PLA 2 ) in heterologous system (E. coli). The Diplodus annularis PLA 2 (DaPLA 2 ) was then refolded from inclusion bodies and purified by Ni-affinity chromatography. We used the pH-stat method (with emulsified phosphatidylcholine as substrate) and the monomolecular film technique (using various glycerophospholipids substrates spread in the form of monomolecular films at the air–water interface) to access the biochemical and kinetic properties of the recombinant DaPLA 2 . The DaPLA 2 was found to be active and stable at higher temperatures (37–50 °C) than expected. Interestingly, DaPLA 2 hydrolyzes efficiently both purified phosphatidylglycerol and phosphatidylethanolamine at 20 mN/m. These analytical results corroborate with the fact that the catalytic activity of DaPLA 2 , measured with the pH-stat using egg yolk as substrate, is mainly due to the hydrolysis of the PE fraction present in egg yolk, whereas the phosphatidylglycerol is a hallmark substrate for the most secreted PLA 2 -IB.