Comparison of six mammalian lysophospholipases.

Lysophospholipases participate in the regulation of the levels of lysophospholipid, compounds with pleiotropic biological effects. Lysophospholipases were purified from a macrophage cell line (WEHI 265.1), a myelocytic leukemia cell line (HL-60) and peripheral blood eosinophils. WEHI 265.1 cells contain three lysophospholipases 28, 27 and 110 kDa as determined by polyacrylamide gel electrophoresis. The 110 kDa lysophospholipase also exhibits phospholipase A2 activity and appears to be identical to a previously described 110 kDa phospholipase A2. Similarly, the HL-60 cells have three lysophospholipases, the largest again a 110 kDa enzyme with phospholipase A2 activity and the 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 radically different, e.g., 15 of the 20 amino acids of the C-terminal sequences of the HL-60 enzymes are identical. A single lysophospholipase, approx. 15 kDa, is a major eosinophil protein. This enzyme is different from those described above.