[Biochemical and immunological properties of 34kDa EDTA-extractable protein (EEP34k)]

It has been reported that the 34kDa protein of EDTA-extractable protein (EEP34k) cross-reacted with lipocortin antisera. The lipocortins are a family of proteins that have been reported to inhibit phospholipase A2. Previously, we purified two proteins from EEP34k by anion-exchange chromatography, and referred to them as 34k (A) and 34k (B). On Western-blot analysis, two proteins showed cross-reactivity to both lipocortin I and lipocortin II. In this study, four proteins (34k (A)1, 34k (A)2, 34k (B)1, 34k (B)2) were isolated from 34k (A) and 34k (B), on a cation-exchanged chromatography. By peptide mapping, immunological analysis and SDS/PAGE, we confirmed that 34k (A)1 and 34k (B)2 were identified proteins and these were called lipocortin I, and that 34k (A)2 was lipocortin II. It is concluded that at least two lipocortins, I and II are present in EEP34k. We also observed the presence of phospholipase A2 inhibitory activity in both 34k (A) and 34k (B).