Phospholipase a2 represents a class of heatstable, calciumdependent enzymes catalyzing the hydrolysis of the 2acyl bond of 3nphosphoglycerides. Phospholipase a2 structurefunction, mechanism, and signaling. The key role is played by phospholipases from the a 2 superfamily. Anti phospholipase a2 receptor antibody in membranous nephropathy. Because phospholipase a2 pla2 activity is an important component of venom toxicity, we sought candidate pla2 inhibitors by directly testing drugs. Phospholipase a2 pla2 catalyzes the hydrolysis of the sn2 position of membrane glycerophospholipids to liberate arachidonic acid aa, a precursor of. Dr lal pathlabs offers test service for phospholipase a2 receptor antibody pla2r test for checking disorders of kidney. The crystal structure of acidic phospholipase a2 apla2 from agkistrodon halys pallas covalently modified by pbromophenacylbromide pbpb was determined to a resolution of 2. Phospholipase a2, which exists various isoforms, is an enzyme that is overactive during cerebral ischemia due to the influx of calcium into the cell. Cytosolic phospholipase a2 an overview sciencedirect. The catalytic mechanisms of interfacial enzymes acting directly on the interfacial surface of the membrane are notoriously difficult to study experimentally with xray crystallography and other biophysical methods.
This enzyme is named phospholipase a2 to denote its 2acyl specificity uthe 1971. The following assay has been found to be reproducible in our laboratory. Pla2 is elevated in a wide range of inflammationrelated disorders and is considered a good marker for. Phospholipase a phospholipase a1 cleaves the sn1 acyl chain where sn refers to stereospecific numbering phospholipase a2 cleaves the sn2 acyl chain. Antiphospholipase a2 receptor antibody and spontaneous. Abstract phospholipase a2s pla2s are a group of enzymes that hydrolyze the sn2 position of phospholipids to release typically unsaturated fatty acids and lysophospholipids, which serve as precursors for a variety of bioactive lipid mediators. Usa home product directory biochemicals and reagents enzymes, inhibitors, and substrates enzyme substrates substrates by enzyme phospholipase a2.
Of the five major pla2 classes,1 two have been implicated in the progression of atherosclerosis and its complications. Phospholipase a2 pla2 designates a class of enzymes that hydrolyze the sn2 ester of glycerophospholipids to produce a fatty acid and a lysophospholipid. The present invention relates to phospholipase a 2 inhibitor. Varespladib ly315920 appears to be a potent, broad. Introduction ercp is a therapeutic procedure which carries a 5% risk of pancreatitis. Surprisingly, varespladib and its orally bioavailable prodrug, methylvarespladib showed highlevel secretory pla2 spla2 inhibition at nanomolar and picomolar concentrations against 28 medically. Acute respiratory distress syndrome ards is a lifethreatening lung injury that is characterized by arterial hypoxemia and noncardiogenic pulmonary oedema. Structural studies of phospholipase a2inhibitor complexes suggest how the lipolysis reaction is catalyzed. Pdf phospholipase a2 and inflammation researchgate.
Phospholipase a2 substrates by enzyme sigmaaldrich. Isolation of the phospholipase a2 from crotalus oreganus. Antiphospholipase a2 receptor pla2r antibodies are highly specific for the diagnosis of primary membranous nephropathy. K a novel and potent azetidinone inhibitor of the lipoprotein associated phospholipase a. The phospholipase a2 receptor 1 pla2r1 is the major autoantigen in patients suffering from membranous nephropathy. Cellular pathology foxfolipasa by snake venom phospholipase a2 myotoxins and neurotoxins. Phospholipase a 2 is an important enzyme in the arachidonic acid. Pdf phospholipase a2 structurefunction, mechanism, and signaling. Membranes serve as allosteric activators of phospholipase. Phospholipase a2 from puff adder bitis arietans venom. Their action causes an accumulation of fatty acids such as arachidonic acid and docosahaxaenoic acid that can decouple oxidative phosphorylation and alter the permeability of the cell membrane and.
This kits takes our standalone assay for phospholipase a1, pla1 a10070 and combines the necessary reagents to run 2 to 10 complete 96 well microplate assays that monitor activity in purified enzyme preparations and cell lysates. The first is the structure of the pla2 from the venom of the chinese cobra naja naja atra in a complex with a phosphonate transitionstate analogue. Phospholipase a2 definition of phospholipase a2 by. To date, the lack of endogenous glomerular expression of pla2r1 in mice and rats has impeded the establishment of pla2r1dependent animal models of this disease. Cytosolic phospholipase a 2 cpla2 is a calciumdependent enzyme that cleaves fatty acids, such as arachidonic acid, from phospholipids by hydrolyzing the sn2 acyl bond leslie, 1997. A human nonpancreatic secretory pla2 hnpspla2 has been identified that is found in high concentrations in the synovial fluid of patients with rheumatoid arthritis and in the plasma of patients with septic shock. A novel antiinflammatory role for secretory phospholipase a2 in. We followed up a pregnant woman with primary membranous nephropathy during. Lysosomal phospholipase a2 pla2g15 is a ubiquitous enzyme uniquely characterized by a subcellular. Lipoproteinassociated phospholipase a2, plateletactivating. As many as 70% to 75% of patients with primary membranous nephropathy are positive for antipla2r. Secretory phospholipase a 2 spla 2 acts to hydrolyze phospholipids from the surface of cell membranes, native lipoproteins and oxidativelymodified lipoproteins to generate multiple bioactive lipids that include arachidonic acid, nonesterified fatty acids nefa, lysophospholipids lyso.
Phospholipase a2 group ib pla2gib is a sensitive marker of pancreatitis. The activation of phospholipase a2 is believed to have an important role in the inflammatory process owing to its induction of eicosanoids, platelet activating factor. Phospholipase a 2 is one of the most intensively studied membrane proteins which hydrolyzes phospholipids at the sn2 position to form fatty acid and lysophospholipid products. One feature of ards is an alteration of pulmonary surfactant that increases surface tension at the airliquid interface and results in alveolar collapse and the impairment of gas exchange. The importance of phospholipases in cellular signaling, lipid metabo. Desolvation map of the iface of phospholipase a2 sciencedirect. Recent studies have shown that in approximately 70% of patients with primary mn pmn, the immune complexes consist of autoantibodies against the podocyte protein mtype phospholipase a2 receptor. There are four major classes, termed a, b, c and d, which are distinguished by the type of reaction which they catalyze. One unit releases one micromole titratable fatty acid per minute from lecithin emulsion at ph 8. The development of a theoretical framework for the proper analysis of inhibitors is presented.
Activation of pla2 is observed under pathological conditions where. A rapid, quantitative, pointofcare poc test for pla2gib has been developed. Many of these products are believed to play an important role in the inflammatory process. Membraneassociated phospholipase a2 mpla2 is an enzyme that hydrolyses the sn2 fatty acyl ester bond of phosphoglycerides.
Here, we generated a transgenic mouse line expressing murine fulllength pla2r1 in podocytes. Most patients who have undergone ercp are admitted overnight for observation as it can take up to 12 hours for postercp pancreatitis to manifest. Pla2 enzymes are an important pharmacological target implicated in various inflammatory diseases. View details of cost of test, pretest information and. Phospholipase a2 enzymes in metabolic and cardiovascular. A novel mouse model of phospholipase a2 receptor 1. Phospholipase a2 pla2 is the key enzyme that initiates the arachidonic acid cascade, which leads to the generation of multiple eicosanoid products. Computational chemistry, organic synthesis, and in vitro assays were employed to develop potent and selective inhibitors for group via calciumindependent. This enzyme is typical of a large, wellstudied homologous family of pla2s. These are small proteins and the 3d structures are known to high resolution for several species. Bactericidal properties of murine intestinal phospholipase a2. Neurodegenerative disorders with high brain iron include parkinson disease, alzheimer disease and several childhood genetic disorders categorized as neuroaxonal dystrophies. Membranous nephropathy mn is a rare disease in which immune complexes deposit at the glomerular basement membrane, causing damage to the filtration barrier, resulting in proteinuria. The caindependent pla 2 s group viaf do not show any preference for fatty acid at the sn2 site and are.
Phospholipase a2 has been isolated from pancreas, snake and bee venoms. Among the pla2 superfamily, secreted pla2 spla2 enzymes comprise the largest subfamily that includes 11 isoforms with a conserved hisasp. Interisland mutation of a novel phospholipase fosfolkpasa from trimeresurus flavoviridis venom and evolution of crotalinae group ii phospholipases a2. Activation of phospholipase a2 by hsp70 in vitro sciencedirect. A phospholipase is an enzyme that hydrolyzes phospholipids into fatty acids and other lipophilic substances. Pdf phospholipase a2 structurefunction, mechanism, and. Although highly potent 2oxoester inhibitors of giva cpla2 have been developed, their rapid degradation in human plasma limits their pharmaceutical. This particular phospholipase specifically recognizes the sn2 acyl bond of phospholipids and catalytically hydrolyzes the bond, releasing arachidonic acid and lysophosphatidic acid.
Phospholipase a2, which exists various isoforms, is an enzyme that is overactive during. Cytosolic phospholipase a 2 and monoacylglycerol lipase. Membranous nephropathy mn is one of the most common causes of nephrotic syndrome in native kidney biopsies from adults. Development of potent and selective inhibitors for group. A phospholipase a, from bites arientans venom was unified by chmmatogra hit procedures involving cmcellulose, sephadex g50, cmelluose and cellulose phospate p11. A chemical description of the action of phospholipase a2 pla2 can now be inferred with confidence from three highresolution xray crystal structures. Overexpression of group ii phospholipase a2 in human. Phospholipase a2 pla2 catalyses the release of arachidonic acid for generation. We are the only commercial lab currently offering pla2 level measurement as a urine test. Phospholipase a 2 enzymatic activity generates lipid products with biological properties and functions. Phospholipase a2 antagonists, such as aacof3, aca, bel, and ono figure 3, inhibit. Lipoproteinassociated phospholipase a2 is an independent marker for coronary endothelial dysfunction in humans.
Secreted phospholipases a2 pla2s are a family of rela tively stable enzymes. S s harwig, l tan, x d qu, y cho, p b eisenhauer, and r i lehrer department of medicine, ucla school of medicine 90024. The molecular weight of 14,000 was determined on sds gel. Butyphthalide in the treatment of massive cerebral infarction variance in total levels of phospholipase c zeta plczeta in human sperm may limit the applicability of quantitative immunofluorescent analysis as a diagnostic indicator. In both cases the signal saturates at 35 dtpme for all mutants although the maximum signal intensity depends on the position of the trpsubstitution. Phospholipase a2 pla2 is thought to play a key role in cell signaling by. Lppla 2 is a calciumindependent phospholipase a2 enzyme that is associated with both lowdensity lipoprotein ldl and, to a lesser extent, highdensity lipoprotein hdl in human plasma and serum 1 and is distinct from other such phospholipases such as cpla 2 and spla 2.
Human a2 phospholipases pla2s propagate inflammation by producing arachidonic acid precursors from membrane glycerophospholipids, which suggests this enzyme system as a promising drug target. Phospholipase a 2 proteins are of high pharmaceutical concern since they are responsible for the release of arachidonic. This scientific study is, to our knowledge, the first to highlight similarities and differences in the extraction and binding of a phospholipid molecule into the substrate binding. In addition, the use of autoantibodies to mtype phospholipase a2 receptor pla2r as a serologic marker throughout pregnancy and postpartum in the mother and baby is not yet fully elucidated. It has become clear that some of these enzymes liberate arachidonic acid in mammalian cells for the biosynthesis of eicosanoids, and thus there has been considerable interest in developing pla2 inhibitors. Phospholipase a2 receptor autoantibodies, igg labcorp. Values reported in the literature for highly purified venom phospholipase a2 have ranged from 200 to 3000 unitsmg. Finally, some recent results on the use of phospholipase a2 inhibitors in living cells and tissues are revealed. The increased morbidity, mortality, and ineffective treatment associated with the pathogenesis of chronic inflammatory diseases such as asthma and chronic obstructive pulmonary disease copd have generated much research interest.
Pdf phospholipase a 2 s pla 2 s are group of enzymes, which cleave phospholipids specifically at sn2 position to liberate free fatty acid. Thus, inhibiting cpla2 would deny pghs substrate and be expected to reduce. Phospholipase a2 receptor antibodypositive pregnancy. Secreted phospholipases a2 pla2s are a family of rela tively stable. The purified enzyme was characterized as a phosphatide arylhydrolase ec 3.
The antipla2r elisa igg test kit is intended for the qualitative or semiquantitative determination of igg class autoantibodies against phospholipase a2 receptor pla2r in human serum. More specifically, the present invention relates to a phospholipase a 2 inhibitor containing lysophospholipid causes and pathogenic mechanisms of various inflammatory diseases is a wide variety, activation of phospholipase a 2 are known as one of the causes. Phospholipase article about phospholipase by the free. The involvement of phospholipases a2 in asthma and chronic. The phospholipase a 2 pla 2 family of proteins includes lipolytic enzymes that liberate the sn2 fatty acyl chains from phospholipids to yield nonesterified fatty acids and lysophospholipids. Secretory phospholipase a2 generates the novel lipid.
Phospholipase a2 enzymes and the risk of atherosclerosis. Pla2g6, encoding a phospholipase a2, is mutated in. Oc074 novel point of care test for detection of human. Alphatype phospholipase a2 inhibitors from snake blood core. A titer increase, decrease, or disappearance generally precedes a change in clinical status. In 2009, antibodies to the mtype receptor of phospholipase a2 antipla2r were identified in idiopathic mn patients, both within the kidney and in. Phospholipase a2 inhibition for inflammatory skin diseases. Renal course and clinical outcomes in pregnant women with primary membranous nephropathy are not completely understood.
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