CLONING AND EXPRESSION OF CDNA-ENCODING RAT-LIVER 60-KDA LYSOPHOSPHOLIPASE CONTAINING AN ASPARAGINASE-LIKE REGION AND ANKYRIN REPEAT

Mammalian tissues contain small form and large form lysophospholipases . Here we report the cloning, sequence, and expression of cDNA encodin g the latter form of lysophospholipase using antibody raised against t he enzyme purified from rat liver supernatant (Sugimoto, H., and Yamas hita, S. (1994) J. Biol. Chem. 269, 6252-6258). The 2,539-base pair cD NA encoded 564 amino acid residues with a calculated M-r of 60,794. Th e amino-terminal two-thirds of the deduced amino acid sequence signifi cantly resembled Escherichia coli asparaginase I with the putative asp araginase catalytic triad Thr-Asp-Lys and was followed by leucine zipp er motif. The carboxyl-terminal region carried ankyrin repeat. When th e cDNA was transfected into HEK293 cells, not only lysophospholipase a ctivity but also asparaginase and platelet-activating factor acetylhyd rolase activities were expressed. Reverse transcription-polymerase cha in reaction revealed that the transcript occurred at high levels in li ver and kidney but was hardly detectable in lung and heart from which large form lysophospholipases had been purified, suggesting the presen ce of multiple forms of large form lysophospholipase in mammalian tiss ues.