Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.4.3 (phospholipase C)
18,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hemolytic activity of the culture supernatant of Leptospira interrogans serovar canicola strain Moulton grown in protein-free medium was demonstrated. The activity began to appear in the late logarithmic phase of growth of the organism and reached a plateau after 2 weeks of cultivation. It was inactivated by the addition of dipotassium ethylenediaminetetraacetate, but was effectively restored by Mg2+. Hemolysis by the culture supernatant was stimulated by "hot-cold" incubation. Sleep erythrocytes treated with the culture supernatant of the organism were transformed into spherocytes, in which invagination was observed. A hemolysis inhibitor in rabbit serum was found to be in the chloroform-methanol soluble fraction of the serum. The hemolysin of Leptospira may be phospholipase C.
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PMID:Hemolytic activity of Leptospira interrogans serovar canicola cultured in protein-free medium. 681 53

When guinea-pig liver microsomes were exposed to phospholipase C the rate of phospholipid hydrolysis exceeded the rate of decrease in 17 beta-hydroxysteriod dehydrogenase (17 beta-HSD) activity. The time-course of the decrease in 17 beta-HSD activity was biphasic. An initial more rapid decrease (30-50% of total) was associated with the major extent (85%) of phospholipid hydrolysis. Subsequently, a second, slower phase of 17 beta-HSD inactivation was observed. The addition of purified phospholipids did not reactivate 17 beta-HSD but did protect against the inactivation seen in the second phase. The diacyglycerides produced by phospholipase C action remained associated with the microsomes. It is proposed that the differences in the rates of 17 beta-HSD inactivation reflect variations in the distribution of a single form of 17 beta-HSD among differing membrane fractions rather than the existence of multiple enzyme forms. The stabilizing effects of phospholipids may be due to their ability to prevent changes in lipid-lipid, lipid-protein and protein-protein interactions resulting from diacylglyceride formation. Resuspended microsomal lipids (chloroform-methanol extracts) inactivated 17 beta-HSD suggestive of the presence of endogenous lipid modulators of enzymatic activity.
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PMID:Inactivation of microsomal 17 beta-hydroxysteroid dehydrogenase by phospholipase C: rates of phospholipid hydrolysis and enzyme inactivation, and effects of phospholipids. 695 88

Separation of phosphorylated sarcoplasmic reticulum (SR) fragments by polyacrylamide gel disc electrophoresis in the presence of Na-DS revealed that the radioactivity is distributed in protein zones with molecular weights of 95,000 and 6000-8000. The phosphorylation of the protein with m. w. of 95,000 is Ca2+-dependent. The tryptic hydrolysis of the phosphorylated SR fragments from fast skeletal muscles results in a loss of radioactivity by 60-70%; phospholipase C from Clostridium welchii reduces the labelled phosphate content by 40-50%. The cAMP-dependent protein kinase inhibitor decreases the phosphorylation of both substrates. The substrate of phosphorylation with m. w. of 6000-8000 is not stained with Amidoschwartz 10B or Coumassie brilliant blue. Extraction by an acidified chlorophorm--methanol mixture results in a proteolipid with specific radioactivity exceeding that of the original preparation of phosphorylated SR membranes 3-4-fold. Thin-layer chromatography on Silufol plates and Silicagel KSK showed that the proteolipid is not chromatographically homogeneous after 2-fold precipitation by diethyl ether and is localized in a band with Rf varying from 0.6 to 0.8. The fluorescence spectrum of the proteolipid in a chlorophorm--methanol--HCl solution is represented by an assymmetrical structure-free band with a maximum at 350 nm. A possible role of phosphorylase b and proteolipid in manifestation of the functional activity of the SR fragments is discussed.
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PMID:[Characterization of endogenous phosphorylation substrates of sarcoplasmic reticulum fragments from fast skeletal muscles of the rabbit]. 711 8

The iodoplatinate (IP) reaction, a selective method for visualization of phospholipids, was applied to the predentine and dentine of rat incisors and compared with malachite green aldehyde (MG) fixation/staining. Spot tests indicated (1) that IP specifically stains phospholipids, but not amino acids, displaying as do phospholipids, quaternary ammonium groups; and (2) phosphatidylserine and sphingomyelin were also stained by MGA. Although this reagent is known to interact with phosphorus, phosphoproteins remained unstained. In the rat incisor, an IP-positive network including granules and thin filaments was seen in predentine in the inter-collagen spaces, in many cases closely associated with collagen fibres and their periodic striations. In dentine, positively stained needle-like structures were located along individual collagen fibres, or at the surface of groups of collagen fibres. This staining pattern was unchanged on sections of material pretreated with acetone, whereas the staining was abolished or markedly reduced when the samples were treated either with chloroform/methanol or phospholipase C prior to the IP reaction. Pretreatment of the samples with hyaluronidase promoted subsequent diffusion of the staining. A very similar staining pattern was observed with MGA, in accordance with earlier reports. The present findings validate the histochemical results reported previously on the distribution and potential role(s) of phospholipids in dentine biomineralization.
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PMID:Iodoplatinate visualization of phospholipids in rat incisor predentine and dentine, compared with malachite green aldehyde. 751 28

Parathyroid hypertensive factor (PHF) has been purified from two sources of material: plasma of spontaneously hypertensive rats (SHRs) and culture medium from organ culture of SHR parathyroid glands. Chromatographic characteristics of PHF from these two sources are identical. Biological activity of PHF (assayed as the characteristic delayed hypertensive response in normotensive rats) is sensitive to degradation by treatment in base, and the enzymes trypsin, chymotrypsin, phospholipase C, and phospholipase D. PHF activity may also be extracted from source material with chloroform: methanol (4:1). A hypothetical structure for the active component of PHF is suggested. This is comprised of a peptide liked to a lysophospholipid.
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PMID:Purification and structural characterization of parathyroid hypertensive factor. 751 47

A sensitive quantitative analysis by thin layer chromatography was developed for the determination of platelet activating factor (PAF) and other phospholipids in human saliva. The saliva sample (0.6 ml) was pretreated by diatomite column extraction with chloroform-methanol (95:5, v/v). The extract (20 microliters) was spotted on a TLC plate. The mobile phase was chloroform-methanol-water (65:35:7, v/v). The development proceeded until the mobile phase front reached 8 cm from the spotted point, this process usually required 30 min. After development, phospholipase C and alkaline phosphatase solutions were sprayed on the TLC plate at 45 degrees C to hydrolyze phospholipids. By spraying a mixture of ammonium molybdate and Malachite Green, the produced phosphate was changed to molybdophosphate-Malachite Green aggregate, which gave a blue green spot. The colored spots were scanned at 620 nm by chromatoscanner. A linear relationship was obtained between peak area and PAF concentration in the range from 2 to 100 pmol/spot with a relative standard deviation of 2% (n = 7). By this procedure, lysophosphatidylcholine, phosphatidylcholine and phosphatidylethanolamine in human saliva were also determined sensitively. PAF levels in the range from 40 to 300 ng/ml were found in normal human salivas. Although differences in the total amounts of phospholipids in saliva were found for each healthy volunteer and sampling time, the composition of phospholipids was proved to be virtually constant.
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PMID:[Densitometric quantitation of platelet activating factor and other phospholipids in human saliva using enzyme reaction on a silica plate]. 796 53

Brain tissue and serum from mice intracerebrally injected with 1 microgram of staphylococcal alpha-toxin contained elevated amounts of a naturally occurring brain tissue component(s) called muscle-relaxing factor (MRF). MRF induced reversible, generalized, flaccid paralysis of mice after intracerebral but not intraperitoneal or intravenous administration. MRF (i) was soluble in Hanks balanced salt solution and in acidified (pH 2) Hanks balanced salt solution, in which it partitions into ethyl acetate, acetone, and methanol; (ii) was separated from some pigments by thin-layer chromatography on silica gel plates; (iii) did not comigrate with prostaglandin and leukotriene standards during high-pressure liquid chromatography with a mu Bondapak fatty acid column; and (iv) did not contain amino acids, exhibit absorption maxima at a wavelength range of 210 to 600 nm, or fluoresce when exposed to UV light. MRF has been detected in rabbit brain that has been stored frozen at -70 degrees C and has been enhanced in vitro in slices of both mouse and rabbit brain following incubation of the brain slices with staphylococcal alpha-toxin. Studies to identify the chemical nature of MRF and the mechanism by which, in mice, it induces reversible, flaccid paralysis of voluntary muscle are continuing.
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PMID:Induction of muscle-relaxing factor by staphylococcal alpha-toxin. 830 Feb 2

We examine here the biochemical properties and epididymal localization of a maturation dependent ram sperm surface antigen. A monoclonal antibody, ESA152, identifies an antigen that is present on the surface of ejaculated sperm, but is absent from testicular sperm. Crosslinking of the ESA152 antigen with bivalent antibodies induces the acrosome reaction, redistributing the antigen into the anterior region of the sperm head where it associates with the fusion product of the plasma membrane and the outer acrosomal membrane. The ESA152 antigen appears as a polypeptide of 18 kDa on immunoblots of SDS-polyacrylamide gels. The ESA152 epitope includes the sialic acid termini of N-linked oligosaccharides, as shown by its sensitivity to neuraminidase and endoglycosidase F. The ESA152 antigen is a highly hydrophobic integral membrane protein that resists aqueous extraction, partitions into the detergent phase of Triton-X-114, and solubilizes in chloroform-methanol mixtures. The anchoring of ESA152 is unaffected by phosphtidylinositol specific phospholipase C. The antigen is absent from extracts of caput and corpus epididymidis but appears abruptly in the first segment of the cauda. Immunofluorescence reveals that the ESA152 epitope first appears in clusters of cells in the luminal epithelium of the proximal cauda, prior to or concurrent with its appearance on sperm.
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PMID:Biochemical characterization and epididymal localization of the maturation-dependent ram sperm surface antigen ESA152. 835 35

Lipophosphoglycan-like glycoconjugates were isolated, purified and partially characterized from Tritrichomonas foetus and Trichomonas vaginalis. Cell surface radiolabeling of both trichomonads by the galactose oxidase/NaB[3H]4 technique indicated that the glycoconjugate was located on the cell surface of the parasites. The glycoconjugates were extracted from the delipidated residue fraction with the solvent, water/ethanol/diethylether/pyridine/NH4OH (15:15:5:1:0.017) and were purified to homogeneity by Sepharose CL-4B followed by octyl-Sepharose chromatography and methanol precipitation. The glycoconjugates migrated as broad bands upon SDS-PAGE. The T. foetus glycoconjugate contained large amounts of fucose along with some mannose, galactose, glucosamine and glucose and trace amounts of galactosamine and inositol. The T. vaginalis glycoconjugate appeared to contain large amounts of glucosamine and galactose along with some glucose, mannose and traces of galactosamine and inositol. The surface-labeled glycoconjugates from both parasites was found to be deaminated with nitrous acid and susceptible to phosphatidylinositol-specific phospholipase C, indicating the presence of a phospholipid anchor. Furthermore, these glycoconjugate were found to contain phosphate and were labile to hydrolysis by mild acid, strongly suggesting that the intact molecule is related to Leishmania lipophosphoglycans (LPG). The most striking and the unique features of these glycoconjugate molecules are the presence of large amounts of fucose in T. foetus and glucosamine in T. vaginalis along with the presence of galactosamine in both parasites. These results indicate that these glycoconjugates are new types of LPG-like molecules expressed on the trichomonad cell surface and are structurally distinct from Leishmania LPG.
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PMID:Lipophosphoglycan-like glycoconjugate of Tritrichomonas foetus and Trichomonas vaginalis. 843 19

We have isolated the core aldehydes (aldehydes still bound to parent molecules) of phosphatidylcholine (PC) and cholesteryl esters (CE) from copper-catalyzed peroxidation of human plasma low (LDL) and high (HDL) density lipoproteins. The aldehydes were isolated by extraction with acidified chloroform-methanol containing 2,4-dinitrophenylhydrazine. The 2,4-dinitrophenylhydrazone (DNPH) derivatives formed were resolved by reversed phase high performance liquid chromatography (HPLC) and identified by on-line quadrupole mass spectrometry (LC/MS). The major PC core aldehydes from oxidized LDL and HDL were identified as 1-palmitoyl-(1-stearoyl) 2-(9-oxononanoyl)-, 1-palmitoyl-(1-stearoyl) 2-(8-oxooctanoyl)-, and 1-palmitoyl-(1-stearoyl) 2-(5-oxovaleroyl)-sn-glycerols after phospholipase C digestion of the DNPH derivatives of the phospholipids. The major aldehydes from peroxidation of cholesteryl esters were the 9-oxononanoyl, 8-oxooctanoyl, and 5-oxovaleroyl esters of cholesterol and 7-ketocholesterol. The core aldehydes were estimated to account for a minimum of 1-2% of the consumed linoleate and arachidonate esters. A relatively smaller yield of the PC core aldehydes from LDL compared to HDL was attributed to the presence of greater amounts of phospholipases in LDL than in HDL. More comparable yields of PC core aldehydes were obtained in the presence of phenylmethylsulfonylfluoride, which inhibits phospholipases. We conclude that peroxidation of LDL and HDL results in formation of detectable amounts of cholesteryl and glycerophospholipid esters containing aldehyde functions. The yield of PC aldehydes varies with the activity of the platelet activating factor (PAF) acetyl hydrolase.
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PMID:Lipid ester-bound aldehydes among copper-catalyzed peroxidation products of human plasma lipoproteins. 855 76


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