TAILIEUCHUNG - Báo cáo khoa học: The identification of a phospholipase B precursor in human neutrophils

A phospholipase B (PLB) precursor was purified from normal human gran-ulocytes using Sephadex G-75, Mono-S cation-exchange and hydroxyapa-tite columns. The molecular mass of the protein was estimated to be 130 kDa by gel filtration and 22 and 42 kDa by SDS⁄PAGE. | ỊFEBS Journal The identification of a phospholipase B precursor in human neutrophils Shengyuan Xu Linshu Zhao Anders Larsson and Per Venge Department of MedicalSciences ClinicalChemistry Uppsala University Sweden Keywords granulocytes inflammation neutrophils phospholipase B phospholipids Correspondence Shengyuan Xu Department of Medical Sciences Clinical Chemistry Uppsala University SE-751 85 Uppsala Sweden Fax 46 18 611 3703 Tel 46 18 611 4204 E-mail Received 14 August 2008 revised 14 October 2008 accepted 30 October 2008 doi A phospholipase B PLB precursor was purified from normal human granulocytes using Sephadex G-75 Mono-S cation-exchange and hydroxyapatite columns. The molecular mass of the protein was estimated to be 130 kDa by gel filtration and 22 and 42 kDa by SDS PAGE. Tryptic peptide and sequence analyses by MALDI-TOF and tandem mass spectrometry MS MS identified the protein as a FLJ22662 Homo sapiens gene product a homologue of the amoeba Dictyostelium discoideum PLB. The native protein needed modifications to acquire deacylation activity against phospholipids including phosphatidylcholine phosphatidylinositol phosphatidylethanolamine and lysophospholipids. Enzyme activity was associated with fragments derived from the 42 kDa fragment. The enzyme revealed a PLB nature by removing fatty acids from both the sn-1 and sn-2 positions of phospholipids. The enzyme is active at a broad pH range with an optimum of . Immunoblotting of neutrophil postnuclear supernatant using antibodies against the 42 kDa fragment detected a band at a molecular mass of 42 kDa indicating a neutrophil origin of the novel PLB precursor. The existence of the PLB precursor in neutrophils and its enzymatic activity against phospholipids suggest a role in the defence against invading microorganisms and in the generation of lipid mediators of inflammation. The neutrophil plays an important role in both innate immunity and in

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