COMPARISON OF 6 MAMMALIAN LYSOPHOSPHOLIPASES

Lysophospholipases participate in the regulation of the levels of lyso phospholipid, compounds with pleiotropic biological effects. Lysophosp holipases were purified from a macrophage cell line (WEHI 265.1), a my elocytic leukemia cell line (HL-60) and peripheral blood eosinophils. WEHI 265.1 cells contain three lysophospholipases 28, 27 and 110 kDa a s determined by polyacrylamide gel electrophoresis. The 110 kDa lysoph ospholipase also exhibits phospholipase A2 activity and appears to be identical to a previously described 110 kDa phospholipase A2. Similarl y, the HL-60 cells have three lysophospholipases, the largest again a 110 kDa enzyme with phospholipase A2 activity and t he smaller are 20 and 21 kDa. The low molecular mass lysophospholipases have distinctive chromatographic properties and amino acid compositions. However. the two low molecular mass enzymes from a given cell type are not radicall y different, e.g., 15 of the 20 amino acids of the C-terminal sequence s of the HL-60 enzymes are identical. A single lysophospholipase, appr ox. 15 kDa, is a major eosinophil protein. This enzyme is different fr om those described above.