High expression in adult horse of PLRP2 displaying a low phospholipase activity.

The physiological role of the two lipase-related proteins, PLRP1 and PLRP2, still remains obscure although some propositions have been made concerning PLRP2. In this paper, we report the presence of high amounts of PLRP2 in adult horse pancreas whereas no PLRP1 could be detected. As well, a non-parallel expression of PLRP2 and PLRP1 is observed in adult cat and dog, since no PLRP2 could be detected in these two species. In adult ox, neither PLRP2 nor PLRP1 could be found. These findings are in favor of a different regulation of the expression of the genes encoding pancreatic lipase and the related proteins according to the species. The cDNA encoding horse PLRP2 has been cloned and the protein expressed in insect cells. Both native and recombinant PLRP2 display the same catalytic properties. They possess a moderate lipase activity, inhibited by bile salts and not restored by colipase. Interestingly, they differ from PLRP2 from other species by their very low phospholipase activity indicating that PLRP2 could not be considered as a general phospholipase as previously postulated. This work highlights the variability of the properties of PLRP2 and rises the question of the physiological function of this protein in adult according to the species.