Phospholipase a2

Phospholipase a2 and Regeneration volume 36Article number: 7 Cite this article, phospholipase a2. Metrics details. Within the phospholipase A 2 PLA 2 superfamily that hydrolyzes phospholipids to yield fatty acids and lysophospholipids, the secreted PLA 2 sPLA 2 enzymes comprise the largest family that contains 11 isoforms in mammals.

Federal government websites often end in. The site is secure. The phospholipase A 2 PLA 2 superfamily consists of many different groups of enzymes that catalyze the hydrolysis of the sn-2 ester bond in a variety of different phospholipids. The products of this reaction, a free fatty acid, and lysophospholipid have many different important physiological roles. This review focuses on the superfamily of PLA 2 enzymes, and then uses three specific examples of these enzymes to examine the differing biochemistry of the three main types of these enzymes.

Phospholipase a2

The enzyme phospholipase A 2 EC 3. This particular phospholipase specifically recognizes the sn 2 acyl bond of phospholipids and catalytically hydrolyzes the bond, releasing arachidonic acid and lysophosphatidic acid. Upon downstream modification by cyclooxygenases or lipoxygenases , arachidonic acid is modified into active compounds called eicosanoids. Eicosanoids include prostaglandins and leukotrienes , which are categorized as anti-inflammatory and inflammatory mediators. PLA2 enzymes are commonly found in mammalian tissues as well as arachnid, insect, and snake venom. Due to the increased presence and activity of PLA2 resulting from a snake or insect bite, arachidonic acid is released from the phospholipid membrane disproportionately. As a result, inflammation and pain occur at the site. Additional types of phospholipases include phospholipase A 1 , phospholipase B , phospholipase C , and phospholipase D. Phospholipases A 2 include several unrelated protein families with common enzymatic activity. Two most notable families are secreted and cytosolic phospholipases A 2. The extracellular forms of phospholipases A 2 have been isolated from different venoms snake , [5] bee , and wasp , from virtually every studied mammalian tissue including pancreas and kidney as well as from bacteria. Pancreatic sPLA2 serve for the initial digestion of phospholipid compounds in dietary fat. Venom phospholipases help to immobilize prey by promoting cell lysis [ citation needed ]. This arachidonic acid is then metabolized to form several inflammatory and thrombogenic molecules. Excess levels of sPLA2 is thought to contribute to several inflammatory diseases , and has been shown to promote vascular inflammation correlating with coronary events in coronary artery disease and acute coronary syndrome , [8] and possibly leading to acute respiratory distress syndrome [9] and progression of tonsillitis.

The enzyme contains the six conserved disulfide bonds from 28—44, 26—, 43—99, 50—92, 60—85, and 78—80, as well as the additional disulfide bridge from 11—71 [ 39 ], phospholipase a2. The expanding superfamily of phospholipase Phospholipase a2 2 enzymes: classification and characterization.

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Federal government websites often end in. The site is secure. The data presented in this review were compiled from the cited work. Details about the adapted figures and graphic are available upon request. The phospholipase A2 PLA2 superfamily of phospholipase enzymes hydrolyzes the ester bond at the sn-2 position of the phospholipids, generating a free fatty acid and a lysophospholipid. The superfamily of PLA2 comprises at least six big families of isoenzymes, based on their structure, location, substrate specificity and physiologic roles. Phospholipase A2 PLA2 belongs to the lipolytic family of enzymes that hydrolyze the ester bond at the sn-2 position of the phospholipids. Free fatty acids such as arachidonic acid AA and oleic acid OA are important sources of energy [ 1 ]. Moreover, AA can be processed by cyclooxygenases COXs , lipoxygenases LOXs and cytochrome p CYP enzymes into eicosanoids, which can act as potent mediators of inflammation, cell signaling and carcinogenesis Figure 1 [ 2 , 3 ].

Phospholipase a2

The enzyme phospholipase A 2 EC 3. This particular phospholipase specifically recognizes the sn 2 acyl bond of phospholipids and catalytically hydrolyzes the bond, releasing arachidonic acid and lysophosphatidic acid. Upon downstream modification by cyclooxygenases or lipoxygenases , arachidonic acid is modified into active compounds called eicosanoids. Eicosanoids include prostaglandins and leukotrienes , which are categorized as anti-inflammatory and inflammatory mediators. PLA2 enzymes are commonly found in mammalian tissues as well as arachnid, insect, and snake venom. Due to the increased presence and activity of PLA2 resulting from a snake or insect bite, arachidonic acid is released from the phospholipid membrane disproportionately. As a result, inflammation and pain occur at the site. Additional types of phospholipases include phospholipase A 1 , phospholipase B , phospholipase C , and phospholipase D. Phospholipases A 2 include several unrelated protein families with common enzymatic activity. Two most notable families are secreted and cytosolic phospholipases A 2.

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The majority of sPLA 2 enzymes preferentially hydrolyze anionic substrates [ 18 ]. The fatty acid tails of the substrate are surrounded by the hydrophobic residues Leu-2, Phe-5, Trp, Tyr, and Tyr Am J Physiol Endocrinol Metab. The immune system as a sensor of the metabolic state. A new classification of phospholipases A2 based upon structural determinants. Serine phosphorylation and activation of cytosolic phospholipase A2 by MNK1-related protein kinases. Ser phosphorylation has been shown to cause a very small increase in activity [ , ], however recent work studying membrane binding found a 60 fold increase in membrane affinity at 2. Sorry, a shareable link is not currently available for this article. Within the phospholipase A 2 PLA 2 superfamily that hydrolyzes phospholipids to yield fatty acids and lysophospholipids, the secreted PLA 2 sPLA 2 enzymes comprise the largest family that contains 11 isoforms in mammals. PMC Biochim Biophys Acta.

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We have also shown that this PIP 2 activation requires the presence of the C2 domain, even though the PIP 2 binding site is completely contained on the catalytic domain [ 97 ]. Metabolic regulation by secreted phospholipase A 2. The caspase truncated enzyme was hyperactive and reduced cell viability when overexpressed in HEK cells [ ]. Human pancreatic islets express mRNA species encoding two distinct catalytically active isoforms of group VI phospholipase A2 iPLA2 that arise from an exon-skipping mechanism of alternative splicing of the transcript from the iPLA2 gene on chromosome 22q Active site and catalytic mechanism of phospholipase A2. Phospholipases A 2 can be classified based on sequence homology. Tools Tools. The cytosolic phospholipase A2 catalytic domain modulates association and residence time at Golgi membranes. Inhibition of calcium-independent phospholipase A2 suppresses proliferation and tumorigenicity of ovarian carcinoma cells. The sPLA 2 group of enzymes has a vast variety of physiological functions. Dennis 1, 2.