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The Biochemical Journal Aug 1988A phospholipase A2, Laticauda colubrina phospholipase A2 II (LcPLA-II), and a phospholipase A2 homologue, Laticauda colubrina phospholipase A2 homologue I (LcPLH-I),...
Isolation, properties and amino acid sequences of a phospholipase A2 and its homologue without activity from the venom of a sea snake, Laticauda colubrina, from the Solomon Islands.
A phospholipase A2, Laticauda colubrina phospholipase A2 II (LcPLA-II), and a phospholipase A2 homologue, Laticauda colubrina phospholipase A2 homologue I (LcPLH-I), were isolated from the venom of the yellow-lipped sea snake, Laticauda colubrina, from the Solomon Islands. LcPLA-II showed phospholipase A2 activity towards egg-yolk phosphatidylcholine (24 mumol/min per mg at optimal conditions at 37 degrees C) and lethal potency (LD50 45 micrograms/kg body wt. intravenously in mice). Both of the activities were lost by treatment with p-bromophenacyl bromide. LcPLH-I showed neither phospholipase A2 activity nor lethal potency at a dose of 4.5 mg/kg body wt. in mice. It was not modified by the treatment with p-bromophenacyl bromide. LcPLA-II and LcPLH-I bound Ca2+ at a 1:1 molar ratio with KCa values of 105 microM and 44 microM at pH 8.0 respectively. Elucidation of the amino acid sequences of these two proteins showed that each protein consisted of a single chain of 118 amino acid residues, including 14 half-cystine residues. The two sequences are different from each other at 22 residues and highly homologous to those from other sources. The essential histidine residue for the phospholipase A2 activity at position 48 is replaced by an asparagine residue in the homologue LcPLH-I. Details of the separation of the peptides obtained by proteinase digestions of LcPLA-II and LcPLA-I and the determination of their amino acid sequences are given in Supplementary Publication SUP 50145 (14 pages), which has been deposited at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1988) 249, 5.
Topics: Acetophenones; Amino Acid Sequence; Animals; Chromatography, Gel; Elapid Venoms; Isoenzymes; Lethal Dose 50; Molecular Sequence Data; Peptide Fragments; Phospholipases; Phospholipases A; Phospholipases A2; Sequence Homology, Nucleic Acid
PubMed: 3178739
DOI: 10.1042/bj2530869 -
Chemical Reviews Oct 2011
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Cellular Signalling Jul 2007Signaling proteins are usually composed of one or more conserved structural domains. These domains are usually regulatory in nature by binding to specific activators or... (Review)
Review
Signaling proteins are usually composed of one or more conserved structural domains. These domains are usually regulatory in nature by binding to specific activators or effectors, or species that regulate cellular location, etc. Inositol-specific mammalian phospholipase C (PLC) enzymes are multidomain proteins whose activities are controlled by regulators, such as G proteins, as well as membrane interactions. One of these domains has been found to bind membranes, regulators, and activate the catalytic region. The recently solved structure of a major region of PLC-beta2 together with the structure of PLC-delta1 and a wealth of biochemical studies poises the system towards an understanding of the mechanism through which their regulations occurs.
Topics: Amino Acid Sequence; Animals; Cell Membrane; Enzyme Activation; GTP-Binding Proteins; Humans; Isoenzymes; Molecular Sequence Data; Phospholipase C beta; Phospholipase C delta; Protein Binding; Protein Structure, Tertiary; Type C Phospholipases
PubMed: 17524618
DOI: 10.1016/j.cellsig.2007.04.006 -
Acta Pharmacologica Sinica Dec 2003
Review
Topics: Animals; Gene Expression Regulation; Group II Phospholipases A2; Humans; Phospholipases A; Phospholipases A2; Pulmonary Surfactant-Associated Protein A; Pulmonary Surfactants; Respiratory Distress Syndrome
PubMed: 14653960
DOI: No ID Found -
Bioorganic & Medicinal Chemistry May 2023In this work, we report the design, synthesis, and application of a bis-pyrene phospholipid probe for detection of phospholipase A action through changes in pyrene...
In this work, we report the design, synthesis, and application of a bis-pyrene phospholipid probe for detection of phospholipase A action through changes in pyrene monomer and excimer fluorescence intensities. Continuous fluorometric assays enabled detection of the activities of multiple PLA enzymes as well as the decrease in catalysis by PLA from honey bee venom caused by the inhibitor p-bromo phenacylbromide. Thin-layer chromatography and mass spectrometry analysis were also used to validate probe hydrolysis by PLA. Mass spectrometry data also supported cleavage of the probe by phospholipase C and D enzymes, although changes in fluorescence were not observed in these cases. Nevertheless, the bis-pyrene phospholipid probe developed in this work is effective for detection of PLA enzyme activity through an assay that enables screening for inhibitor development.
Topics: Hydrolysis; Phospholipases; Phospholipases A2; Phospholipids; Pyrenes
PubMed: 37150117
DOI: 10.1016/j.bmc.2023.117301 -
Journal of Biochemistry Dec 1982The subcellular distribution of the phospholipase activities and metabolism of lysophosphatidylcholine in cultured human cell line (FL cells) during "fusion-from-within"...
Release of lysosomal phospholipase A1 and A2 into cytosol and rapid turnover of newly-formed lysophosphatidylcholine in FL cells during fusion-from-within induced by measles virus.
The subcellular distribution of the phospholipase activities and metabolism of lysophosphatidylcholine in cultured human cell line (FL cells) during "fusion-from-within" induced by measles virus were studied. During cell fusion, fairly high activities of phospholipase A1 and A2, the optimal pHs of which were acidic, appeared in the cytosol. These phospholipases were confirmed to be of lysosomal origin by the following facts: (1) the properties of these phospholipases were the same as those of lysosomal phospholipase A1 and A2; (2) a decrease in the total activity of phospholipases A1, A2 and acid phosphatase in the lysosomal fraction of the infected cells coincided with an increase in their activity in the cytosol. The release of lysosomal phospholipase A1 and A2 into the cytosol of the infected cells appeared to be related to the extent of cell fusion-from-within. Phospholipase A1 and A2 released to the cytosol hydrolyzed the cell membrane-bound phospholipids to form lysophospholipids. 1-[1-14C]Palmitoyl-GPC, incorporated into the cells from the culture medium, was rapidly converted into phosphatidylcholine, triacylglycerol and phosphatidylethanolamine in the cells during fusion-from-within, but the radioactive lysophosphatidylcholine and fatty acids were hardly detectable, indicating a rapid turnover of cellular lysophosphatidylcholine during cell fusion. The subcellular lysophospholipid acyl-hydrolase activities of the infected cells were higher than those of normal cells. Possible relation between the membrane fusion induced by measles virus and the phospholipid metabolism in the infected cells were discussed.
Topics: Cell Fusion; Cells, Cultured; Culture Media; Cytosol; Humans; Lysophosphatidylcholines; Lysosomes; Measles virus; Phospholipases; Phospholipases A; Phospholipases A1; Subcellular Fractions
PubMed: 7161254
DOI: 10.1093/oxfordjournals.jbchem.a134098 -
BMC Genomics Dec 2017Nonspecific phospholipase C (NPC), which belongs to a phospholipase C subtype, is a class of phospholipases that hydrolyzes the primary membrane phospholipids, such as...
BACKGROUND
Nonspecific phospholipase C (NPC), which belongs to a phospholipase C subtype, is a class of phospholipases that hydrolyzes the primary membrane phospholipids, such as phosphatidylcholine, to yield sn-1, 2-diacylglycerol and a phosphorylated head-group. NPC plays multiple physiological roles in lipid metabolism and signaling in plants. To fully understand the putative roles of NPC genes in upland cotton, we cloned NPC genes from Gossypium hirsutum and carried out structural, expression and evolutionary analysis.
RESULTS
Eleven NPC genes were cloned from G. hirsutum, which were found on chromosomes scaffold269.1, D03, A07, D07, A08, D11, and scaffold3511_A13. All GhNPCs had typical phosphoesterase domains and have hydrolase activity that acts on ester bonds. GhNPCs were annotated as phospholipase C, which was involved in glycerophospholipid metabolism, ether lipid metabolism, and biosynthesis of secondary metabolites. These GhNPCs showed differential expression patterns in distinct plant tissues and in response to various types of stress (low-phosphate, salt, drought, and abscisic acid). They also had different types and numbers of cis-element. GhNPCs could be classified into four subfamilies. Four pairs of GhNPCs were generated by whole-genome duplication and they underwent purifying selection.
CONCLUSIONS
Our results suggested that GhNPCs are involved in regulating key abiotic stress responses and ABA signaling transduction, and they may have various functional roles for different members under complex abiotic stress conditions. Functional divergence may be the evolutionary driving force for the retention of four pairs of duplicate NPCs. Our analysis provides a solid foundation for the further functional characterization of the GhNPC gene family, and leads to potential applications in the genetic improvement of cotton cultivars.
Topics: Cloning, Molecular; Exons; Gene Expression; Gossypium; Introns; Molecular Sequence Annotation; Multigene Family; Nucleotide Motifs; Phylogeny; Promoter Regions, Genetic; Sequence Alignment; Synteny; Type C Phospholipases
PubMed: 29258435
DOI: 10.1186/s12864-017-4370-6 -
Preventive Cardiology 2006Recently, several epidemiologic studies have demonstrated an association between plasma lipoprotein-associated phospholipase A2 (Lp-PLA2) concentration and risk of... (Review)
Review
Recently, several epidemiologic studies have demonstrated an association between plasma lipoprotein-associated phospholipase A2 (Lp-PLA2) concentration and risk of subsequent cardiovascular events. Several major commercial and reference laboratories across the United States are now offering Lp-PLA2 testing for clinical use to evaluate cardiovascular risk and as a guide to intensity of therapy in individuals at intermediate risk for developing coronary heart disease. Each laboratory has established its own cut points, or "decision values," for Lp-PLA2, which vary from the 50th to the 95th percentile values of individual populations tested at each site. Uniform reporting of cut points has not been achieved. The purpose of this manuscript is to recommend appropriate decision values for Lp-PLA2, endorsed by a consensus panel of laboratorians and clinicians from the major laboratories where the test is performed. These coauthors possess considerable experience with assessment of cardiovascular risk marker decision values in general and are familiar with the validation of the Lp-PLA2 immunoassay and the Lp-PLA2 clinical studies conducted thus far. An ideal risk marker, studied in an ideal population, might yield a consistent cut point associated with a sudden increase in cardiovascular risk. While acknowledging that additional studies will be required to test and refine the recommended decision value, this article reviews the most current information with which to provide guidance to practicing clinicians regarding Lp-PLA2 levels. Since several studies have demonstrated increased risk associated with the second and third tertiles vs. the first tertile for Lp-PLA2, the 50th percentile cut point (235 ng/mL) is recommended as a conservative cut point associated with increased risk for cardiovascular disease. This cut point is not proposed as a treatment target, but rather as a level above which clinicians should consider a patient to be at higher risk for cardiovascular events, independent of established risk factors, high- and low-density lipoprotein cholesterol, and high-sensitivity C-reactive protein.
Topics: 1-Alkyl-2-acetylglycerophosphocholine Esterase; Adult; Biomarkers; Cardiovascular Diseases; Female; Humans; Male; Phospholipases A; Phospholipases A2; Proportional Hazards Models; Reference Values; Sex Factors
PubMed: 16849876
DOI: 10.1111/j.1520-037x.2006.05547.x -
Free Radical Biology & Medicine Jun 2013This article presents a radiometric assay to determine the enzymatic activity of platelet-activating factor (PAF) acetylhydrolase (PAF-AH), also known as...
This article presents a radiometric assay to determine the enzymatic activity of platelet-activating factor (PAF) acetylhydrolase (PAF-AH), also known as lipoprotein-associated phospholipase A2 and phospholipase A2 group 7A. The method is based on the release of radioactively labeled acetate from sn-2-labeled PAF and separation of substrate and product using reversed-phase column chromatography on octadecyl silica gel cartridges. The assay is fast, convenient, reproducible, sensitive, and inexpensive. The instrumentation required includes standard laboratory equipment and a liquid scintillation counter. The assay is also useful to determine the activity of intracellular PAF-AH (PAF-AH II), provided that a few modifications are included. The enzymatic activity determined using PAF as the substrate is a direct indication of the ability of plasma samples, purified preparations, and cellular and tissue lysates to hydrolyze short- and medium-chain phospholipids that may or may not harbor oxidized functionalities. In addition, the assay can be used to test the suitability of other phospholipids, including species containing oxidized, long-chain sn-2 fatty acyl groups, as PAF-AH substrates. This versatile assay can be used to accurately determine PAF-AH activity in biological samples and preliminarily assess affinity and efficiency of the hydrolysis of potential substrates present in complex mixtures.
Topics: 1-Alkyl-2-acetylglycerophosphocholine Esterase; Enzyme Activation; Humans; Phospholipases
PubMed: 22659315
DOI: 10.1016/j.freeradbiomed.2012.05.031 -
Toxicology and Applied Pharmacology Jul 2002Although regulation of uterine contractility is fundamental for parturition, mechanisms by which toxicants modify uterine muscle contractions remain poorly understood....
Although regulation of uterine contractility is fundamental for parturition, mechanisms by which toxicants modify uterine muscle contractions remain poorly understood. In a previous cumulative concentration-response study, 10 microM lindane (gamma-hexachlorocyclohexane) reduced contraction force and 30 microM lindane abolished contractions in Gestation Day 10 rat uterine strips when lindane was added to muscle baths at 10-min intervals. Other studies showed that brief (<10 min) exposures to 10-100 microM lindane inhibit gap junctions and activate phospholipase pathways in rat myometrial cells in culture. Consequently, lindane was used as a prototype toxicant with known uterine activity to investigate the hypothesis that activation of a specific phospholipase pathway provides a mechanistic link between inhibition of uterine contraction and inhibition of myometrial gap junctions. Uterine tissue and cells were pretreated with phospholipase pathway inhibitors to evaluate the role of phospholipase pathways in lindane's actions in the uterus. Concentrations of inhibitors were selected based on previous reports of effective concentrations for the enzyme activity and on pilot toxicity studies of the inhibitors on uterine contraction and gap junction communication. To monitor uterine contractions, longitudinal uterine strips were excised from Gestation Day 10 rats and suspended in isometric muscle baths, consistent with previous experiments. Exposure in vitro for 60 min to 10-50 microM lindane, an effective concentration range for the uterine responses of interest, revealed that 30 microM lindane rapidly abolished contractions. Subsequently, uterine strips were pretreated with phospholipase pathway inhibitors and then challenged with 30 microM lindane, the lindane concentration that elicited maximal inhibition of uterine contraction. Pretreatment with 20-50 microM of the phosphatidylinositol-specific phospholipase C inhibitor 1-O-octadecyl-2-O-methyl-sn-glycerol-3-phosphorylcholine (ET-18-OCH(3)) reversed lindane-induced inhibition of spontaneous uterine contractions. Gap junction intercellular communication was monitored by injecting the fluorescent dye Lucifer yellow into rat myometrial cells grown in culture and assessing dye transfer to adjacent cells using epifluorescence microscopy. Similar to uterine contraction, pretreatment of cell cultures with phospholipase C inhibitors (30 microM ET-18-OCH(3), 50 microM tricyclodecan-p-yl-xanthogenate.K [D609] or 50 microM tricyclodecan-p-yl-xanthogenate.K or 2-nitro-4-carboxyphenyl-N,N-dophenylcarbamate [NCDC]) partially reversed inhibition of dye transfer by 100 microM lindane, a lindane concentration previously shown to abolish myometrial Lucifer yellow dye transfer under similar culture conditions. In contrast, pretreatment with 20 microM of bromoenol lactone (BEL) to inhibit the calcium-independent phospholipase A(2) or 100 mM ethanol to interrupt the phospholipase D pathway failed to prevent inhibition of spontaneous uterine contractions and inhibition of Lucifer yellow dye transfer by lindane (100 microM). These data suggest that lindane inhibits myometrial gap junctions and spontaneous oscillatory contractions by a phospholipase C-mediated pathway.
Topics: Animals; Cell Separation; Female; Fluorescent Dyes; Gap Junctions; Hexachlorocyclohexane; Insecticides; Isoquinolines; Myometrium; Phospholipases; Pregnancy; Rats; Rats, Sprague-Dawley; Uterine Contraction
PubMed: 12140177
DOI: 10.1006/taap.2002.9411