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

---

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

Intact microsomes isolated from rat liver showed no hexose-6-phosphate dehydrogenase activity, but the enzyme was activated by Triton X-100, deoxycholate, NH4OH, glycine/NaOH, lysophosphatidylcholine, phospholipases A and C, pancreatic lipase and cholesterol esterase, and also by sonic treatment. The enzyme activation by deoxycholate, NH4OH and sonic treatments was solely due to solubilization, while that by phospholipase A appeared to be due to the detergent action of the hydrolysis products. On the other hand, the primary effects of phospholipase C, cholesterol esterase and pancreatic lipase might be accounted for by the partial removal of membrane lipids. The results of washing and trypsin digestion experiments suggested that hexose-6-phosphate dehydrogenase is one of the most firmly bound enzymes among the microsomal proteins. The catalytic properties were the same in the solubilized and the membrane-bound, activated enzymes. Feeding the rats on a high carbohydrate diet altered the extent of enzyme activation by sonication and phospholipase C treatment, suggesting that the microsomal membrane would actually undergo changes in the conformation and/or chemical composition under certain circumstances.
...
PMID:Latency of microsomal hexose-6-phosphate dehydrogenase activity. 1 59

A method is described for the isolation of CDP-diglyceride from bovine brain. Yields of the product ranged from 9.2-15.5 mumol per kilogram of tissue, which corresponds to about 1% of the level of phosphatidic acid. Mild alkaline hydrolysis of the product gave three water-soluble phosphate esters which had the same electrophoretic mobilities as CMP, CDP-glycerol and glycerol 3-phosphate. The liponucleotide was quantitatively hydrolysed by CDP-diglyceride hydrolase from Escherichia coli to phosphatidic acid and CMP. No dCMP was recovered in enzymatic or alkaline hydrolysates and it is concluded there can be little or no dCDP-diglyceride in bovine brain. Brain CDP-diglyceride was similar to phosphatidylinositol in that in both lipids stearate was the major saturated fatty acid and arachidonate the most abundant unsaturated fatty acid. This differed significantly from the fatty acid patterns of other metabolically related phospholipids, phosphatidic acid and cardiolipin. Brain CDP-diglyceride was hydrolysed with phospholipase C from Clostridium welchii with the liberation of the diglyceride moiety in high yield. Treatment of the diglyceride with pancreatic lipase showed CDP-diglyceride with the asymmetric distribution of fatty acids characteristic of most mammalian phospholipids, saturated fatty acids being found mostly at position 1 and polyunsaturated fatty acids at position 2. The derived diglyceride acetates were separated into different molecular species by argentation thin-layer chromatography. These analyses showed that 1-stearoyl, 2-arachidonoyl was the major species of brain CDP-diglyceride.
...
PMID:Cytidine diphosphate diglyceride of bovine brain. Positional distribution of fatty acids and analysis of major molecular species. 77 22

rac-Phosphatidyl carnitine and rac-phosphatidyl beta-methylcholine were synthesized by direct condensation of phosphatidic acid and the appropriate alcohols in the presence of 2,4,6-triiso-propylbenzenesulphonylchloride and pyridine. Tetraphenylborates of the quarternary ammonium compounds beta-methylcholine and carnitine benzyl ester were shown to be particularly convenient for synthesis in homogeneous phase. Physical and chemical properties of the two phosphoglycerolipids and some intermediates were described. Phosphatidyl carnitine and phosphatidyl beta-methylcholine were hydrolyzed by phospholipase A2 (phosphatide acyl-hydrolase, EC 3.1.1.4), pancreatic lipase (triacylglycerol acyl-hydrolase, EC 3.1.1.3), and phospholipase C from Bacillus cereus (phosphatidylcholine cholinephosphohydrolase, EC 3.1.4.3). Neither hydrolysis nor transphosphatidylation of phosphatidyl carnitine and phosphatidyl beta-methylcholine was achieved by phospholipase D (phosphatidylcholine phosphatidohydrolase, EC 3.1.4.4). The occurrence of phosphatidyl carnitine in embryonic chicken tissue was suggested by comparison with the synthesized compound. Phosphatidyl carnitine could not be detected in the tissue of rat embryos.
...
PMID:Synthesis and properties of phosphatidyl carnitine and phosphatidyl beta-methylcholine. 80 79

The enzymatic activity of purified phospholipase C (alpha toxin) from Clostridium perfringens was investigated with various phospholipid monolayers. A two-step reaction was used. Enzymatic hydrolysis of insoluble lecithin films by phospholipase C, generating 1,2-diacylglycerol and water-soluble phosphocholine, was coupled with the action of pancreatic lipase in order to give rise to fatty acid and 2-monoacylglycerol, which are rapidly desorbed from the interface. With this new procedure, it is possible to obtain continuous and accurate kinetic measurements of the phospholipase C catalyzed reaction with phospholipid monolayers as the substrate. It is thus possible to avoid the use of radiolabeled substrates as necessary in previous studies, and the difficulties caused by diacylglycerol accumulation in the lipid film are minimized. No hydrolysis was detected when either phosphatidylethanolamine, phosphatidylserine, or phosphatidylglycerol films were used as substrates. By means of a film transfer technique, Ca2+ and Zn2+ ions were found to play a specific and critical role. The present study demonstrates clearly for the first time that Ca2+ is essential for enzyme binding to lipid films, whereas Zn2+ is specifically involved in the catalytic hydrolysis of the substrate.
...
PMID:A new kinetic approach for studying phospholipase C (Clostridium perfringens alpha toxin) activity on phospholipid monolayers. 289 59

The fatty acid esters of chloropropanediol isolated from goat milk fat in small quantities were subjected to a stereospecific analysis via phospholipase C and phosphocholine esters as intermediates. Synthetic rac-1-chloro-2,3-dioleoyl-propanediol was prepared by standard methods and was used as a control. The stereospecific analyses were performed following a release of the fatty acids from the primary positions of each chloropropanediol diester with pancreatic lipase. The resulting X-1-chloro-2-acylpropanediols were then converted into the corresponding phosphocholine derivatives by a stepwise reaction with phosphorus oxychloride and choline chloride. The X-1-chloro-2-acyl-3-phosphocholinepropanediols were subjected to hydrolysis with phospholipase C (C. perfringens), which hydrolyzed 50% of the phosphatide within two min and the rest of it in two hr. From previous experience with glycerol esters, it was assumed that the more rapidly hydrolyzed molecules were the sn-1-chloro-2-acyl-propanediol derivatives and the more slowly hydrolyzed ones the sn-2-acyl-3-chloropropanediol derivatives. A hydrolysis with phospholipase A2 (Crotalus adamanteus) released 50% of the total fatty acid along with the corresponding lyso compound within 10 min, after which there was no further reaction. The hydrolysis products were assayed directly by gas liquid chromatography (GLC) or were isolated by thin layer chromatography (TLC) prior to quantitation by GLC. Both naturally occurring and synthetic chloropropanediol diesters behaved similarly on stereospecific analysis and were therefore concluded to be racemic.
...
PMID:Stereospecific analysis of fatty acid esters of chloropropanediol isolated from fresh goat milk. 372 68

The triacylglycerols of very low density lipoproteins (VLDL) and of chylomicrons were analyzed in the fasting and postabsorptive states from normolipemic subjects and patients with Frederickson's Type II hyperlipoproteinemia, who subsisted on free choice diets, standard diets excluding lard, or were given a breakfast enriched in lard. The VLDL and chylomicrons were obtained by conventional ultracentrifugation, and the triacylglycerols were isolated by thin-layer chromatography (TLC). Representative sn-1,2-, sn-2-3- and sn-1,3-diacylglycerols were generated by partial Grignard degradation of the triacylglycerols and a stereospecific hydrolysis by phospholipase C of the mixed sn-1,2(2,3)-diacyl phosphatidylcholines prepared as intermediates. Representative sn-2-acylglycerols were obtained by hydrolysis with pancreatic lipase. Positional distribution of the fatty acids was established by subtracting in turn the fatty acid composition of the sn-2-position from the fatty acid composition of the sn-1,2- and sn-2,3-diacylglycerols. The molecular association of the fatty acids in the diacylglycerol moieties was determined by gas-liquid chromatography with mass spectrometry (GC/MS) of the tertiary-butyldimethylsilyl (t-BDMS) ethers. The molecular association of the fatty acids in the triacylglycerols was determined by 1-random 2-random 3-random calculation following experimental validation of the distribution. The results confirm a marked asymmetry in the positional distribution of the fatty acids in all triacylglycerol samples, with the palmitic acid predominantly in the sn-1-position, the unsaturated acids about equally divided between the sn-2- and sn-3-positions, and the stearic acid divided about equally between the sn-1- and sn-3-positions. The overall structure of the VLDL and chylomicron triacylglycerols from patients and control subjects was characterized by a non-correlative distribution of fatty acids under all dietary conditions.
...
PMID:Comparative studies of triacylglycerol structure of very low density lipoproteins and chylomicrons of normolipemic subjects and patients with type II hyperlipoproteinemia. 398 38

Diacylphosphatidylethanolamine (PE) was isolated from mouse and rat heart given the same standard diet. The molecular species of PE were determined after conversion of PE into diglycerides by means of hydrolysis with phospholipase C, subsequent hydrolysis with pancreatic lipase and separation of the products by argentation TLC and capillary gaschromatography. Docosahexaenoic acid (22:6n3) containing molecular species and arachidonic acid (20:4n6) containing molecular species represented the major fractions. A preference for stearic acid to combine with poly-unsaturated fatty acids was found. Despite an abundant presence of linoleic acid (18:2n6) in the diet, molecular species containing this fatty acid represented only a minor fraction. The possible physico-chemical and physiological meaning of the presence of molecular species containing many double bonds is discussed.
...
PMID:Molecular species of diacylphosphatidylethanolamine in rat and mouse heart given the same diet. 667 25

In a model bile solution composed of lecithin (L)-bile salt (B), the solubilization of lipid and the accessibility of enzyme to the lipid were examined by observation of EPR spectra and measurement of enzyme activity. The lifetime of the spin probe in the micellar phase was estimated to be approx. 1 microsecond by means of line shape analysis. Both population and lifetime increased with temperature and the molar ratio of lecithin to bile salt (L/B). The EPR data indicated that simple micelle of bile salt, mixed disk micelle of bile salt-lecithin, and multi-lamellar mixed disk micelle can exist in a model bile solution, depending on the L/B molar ratio across a range from 0 to 1.5. The maximal power of the mixed disk micelle to solubilize cholesteryl ester in the model bile at a L/B molar ratio of 1:1 was confirmed by EPR measurement of cholesteryl 12-DOXYL-stearate. Observation of the enzyme activity on a mixture of model bile and substrate at 37 degrees C revealed selective accessibility of cholesterol esterase (bovine pancreas) to mixed disk micelle, of cholesterol oxidase (Streptomyces cinnamomeus) to both simple and mixed disk micelle, and of pancreatic lipase (porcine pancreas) to both simple micelle and an oil droplet of substrate. The temperature-dependent activity of cholesterol oxidase to cholesterol in mixed disk micelle can be explained in terms of mesomorphic phase transition of lecithin side chains followed with fluidity of liquid crystal phase. Regarding phospholipase C from Bacillus cereus, though the selective accessibility to the micelles was not observed at 37 degrees C, a decrease in activity for mixed disk micelle could be found at lower temperatures.
...
PMID:Relation between micellar structure of model bile and activity of esterase. 754 75

The synthesis, identification and characterization of neutral lipid analogs containing N-(7-nitro-2,1,3-benzoxadiazoi-4-yl)-aminocaproic acid are reported. The acyl-imidazole derivative of the fluorescent fatty acid was used to esterify L-alpha-glycerophosphorylcholine. Fluorescent phosphatidylcholines were converted to the corresponding diacylglycerols by phospholipase C digestion. Triacylglycerols were formed by esterification with either fluorescent fatty acid-imidazole or non-fluorescent fatty acid anhydride. The 11 compounds synthesized were identified by a combination of thin layer chromatography, liquid secondary ion mass spectrometry and enzymatic digestion. A solvent system for identifying all eleven analogs by thin layer chromatography is presented. The fluorescence characteristics of these analogs are consistent with previously observed parameters of NBD-lipid analogs, including the density-dependent quenching of analogs containing multiple NBD fluorophores. These analogs mimic native lipids, as evidenced by digestions with the enzymes, porcine pancreatic lipase, phospholipase C and phospholipase A2.
...
PMID:Synthesis and characterization of fluorescent neutral lipid analogs containing N-(7-nitro-2,1,3-benzoxadiazol-4-yl)-aminohexanoic acid. 811 33

The crystal and molecular structure of the Clostridium perfringens alpha-toxin crowns over a century-long research into the mechanisms of pathogenesis of gas gangrene. The structure reveals a two-domain enzyme, with a catalytic all-helical N-terminal domain, and a C-terminal domain similar in its jelly-roll topology to those found in pancreatic lipase and lipoxygenases.
...
PMID:Structure of the gangrene alpha-toxin: the beauty in the beast. 969 39


1 2 Next >>

---