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:3.1.1.5 (neuropathy target esterase)
1,070 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. A comparison of 2-hexadecanoylthio-ethane-1-phosphocholine and 3-hexadecanoylthio-propane-1-phosphocholine and their oxyester counterparts as substrates for some lipolytic enzymes was made. 2. The critical micelle concentration and the transition temperature of the synthetic substrates were compared with the values for 1-hexadecanoyl-sn-glycero-3-phosphocholine. 3. All above-mentioned compounds were deacylated by lysophospholipases. Phospholipase A2 hydrolyzed only the acyl- sulfur- and oxygenester bond in 2-hexadecanoyl-ethane-1-phosphocholine. 4. Kinetic parameters, Km and V, for hydrolysis of these substrates were determined. Km values for thioester substrates were 5--10 fold lower than for the corresponding oxyesters. Maximal hydrolysis rates were 2--5 times higher for the thioesters. 5. Hydrolysis of thioesters by phospholipase A2, lipase and lysophospholipase was shown to proceed by an S-acyl cleavage mechanism. 6. Beef liver lysophospholipase II was rapidly and stoichiometrically inactivated by diisopropylfluorophosphate and bis(p-nitrophenyl) phosphate. Inactivation by the latter inhibitor showed burst-like kinetics. 7. Attempts to show burst-kinetics during the pre-steady state hydrolysis of 2-hexadecanoylthio-ethane-1-phosphocholine by lysophospholipase II were negative. These results are interpreted to indicated that a step prior to deacylation of the enzyme is rate-determining.
...
PMID:A comparison of acyl-oxyester and acyl-thioester substrates for some lipolytic enzymes. 43 7

1. Sonication of bovine liver microsomes completely solubilized the membrane-bound lysophospholipase II (EC 3.1.1.5). Co-chromatography with purified 125I-labelled lysophospholipase indicated that the enzyme was solubilized from microsomes in a lipid-free state. 2. In the presence of residual microsomal membranes, the solubilized lysophospholipase could only be partly degraded by trypsin (EC 3.4.21.4). Therefore, trypsin could not be used to study the transmembrane disposition of lysophospholipase in intact microsomes. 3. Chymotrypsin (EC 3.4.21.1) destroyed the solubilized lysophospholipase activity, even in the presence of residual microsomal membranes. 4. Lysophospholipase in intact microsomal vesicles was resistant to chymotrypsin digestion. 5. When microsomal vesicles were made leaky with lysophosphatidylcholine, chymotrypsin destroyed more than 95% of the lysophospholipase activity. 6. It is concluded from these experiments that at least the active center of lysophospholipase is located at the luminal side of the bovine liver microsomal membrane.
...
PMID:Studies on the transverse localization of lysophospholipase in bovine liver microsomes using proteolytic enzymes. 45 32

1. The transverse distribution of 1-palmitoyl-sn-glycero-3-phospho-N-[Me-13C]-choline in vitro incorporated in sarcoplasmic reticulum has been measured by means of 13C NMR and DyCl3 as an impermeable shift reagent. 2. Lysophosphatidylcholine added to the membranes equilibrates within 30 min at 20 degrees C between outer and inner membrane leaflet so that 42% is located in the inner leaflet. 3. Lysophosphatidylcholine diffuses back from the inner leaflet to the outer upon lysophospholipase action on the outer lysophosphatidylcholine pool.
...
PMID:Transverse distribution and movement of lysophosphatidylcholine in sarcoplasmic reticulum membranes as determined by 13C NMR and lysophospholipase. 47 1

One of the unique features of the chromaffin granule membrane is the presence of about 17 mol% lysophosphatidylcholine. Lysophosphatidylcholine isolated from the granules could be degraded by approx. 94% by lysophospholipase. This result is consistent with chemical analyses data showing that about 9% of this lysophospholipid is 1'-alkenyl glycerophosphocholine. The localization of the acylglycerophosphocholine in the chromaffin granule membrane was studied by using pure bovine liver lysophospholipases. In intact granules only about 10% of the total lysophosphatidylcholine was directly available for enzymic hydrolysis. In contrast, when granule membranes (ghosts) were treated with lysophospholipases approx. 60% of the lysophosphatidylcholine was deacylated. These values did not increase after pre-treatment of intact granules or ghosts with trypsin. Added 1-[1-14C]palmitoyl-sn-glycero-3-phosphocholine did not mix with the endogenous lysophosphatidylcholine pool(s) and remained completely accessible to added lysophospholipases.
...
PMID:Localization of lysophosphatidylcholine in bovine chromaffin granules. 49 99

Alkyl-lysophospholipids inhibit the growth of Meth A sarcoma cells in vitro. In contrast, murine bone marrow macrophages are not sensitive to the destructive effect of these substances. Since alkyl-lysophospholipids are antimetabolites in the synthesis of 3-sn-phosphatidylcholine, tumor cell destruction can be correlated with the disturbance of this metabolism. A decreased synthesis of 3-sn-phosphatidylcholine is accompanied by an increased degradation of cellular 3-sn-phosphatidylcholine in the presence of alkyl-lysophospholipids. As a consequence, endogeneously formed lysophospholipid accumulates, although the lysophospholipase is found to be stimulated. This accumulation of endogeneous lysophospholipids might be due to the fact that a high percentage of these compounds contain an alkyl bond which cannot be split by a lysophospholipase. On the other hand, the reacylation of the formed lysophospholipids is partially blocked as the lysophosphatidylcholine acyltransferase is inhibited by the added alkyllysophospholipids. An accumulation of potentially cytotoxic lysophospholipids in tumor cells might be an additional factor in the tumor cell destruction by alkyl-lysophospholipids.
...
PMID:Disturbance of phospholipid metabolism during the selective destruction of tumor cells induced by alkyl-lysophospholipids. 49 95

1. Lysophospholipase activity solubilized from bovine liver microsomes could be precipitated for more than 80% by antibodies evoked in rabbits against the purified bovine liver lysophospholipase II. 2. After solubilization of the microsomes in 1.5% sodium deoxycholate, an immunoprecipitate containing lysophospholipase II in enzymically active form could be isolated. 3. Microsomal lysophospholipase activity was completely inhibited by [3H]diisopropylphosphofluoridate. Enzyme labelled in this way was isolated by immunoprecipitation from control and chymotrypsin-treated microsomes. Sodium dodecyl sulfate disc gel electrohporesis of the immunoprecipitates showed that chymotrypsin treatment of intact microsomes had no influence on the molecular weight of the enzyme. 4. Attempts to label the lysophospholipase II in microsomes by lactoperoxidase catalyzed iodination or by reaction with the diazonium salt of [125I]iodosulfanilic acid were negative, although both techniques labelled other microsomal proteins efficiently. 5. Antibody absorption experiments gave no indication for the presence of lysophospholipase antigenic sites on the outside surface of microsomes. 6. These experiments are interpreted to indicate that lysophospholipase II is exclusively located at the luminal side of the microsomal membrane.
...
PMID:Studies on the transverse localization of lysophospholipase II in bovine liver microsomes by immunological techniques. 50 78

Changes in the membrane morphology and phospholipid content of human erythrocytes were determined after incubation of intact cells with each of various exogeneous phospholipases (PLases). PLase A2 from Naja naja or bee venom induced crenation of the cells in parallel with hydrolysis of the membrane phosphatidylcholine (PC). This crenated cell shape was reversed to a biconcave disc or cup-like form by a further treatment with lysophospholipase. In contrast, bacterial PLase C from Clostridium perfringens and Pseudomonas aureofaciens or fungal PLase D from Streptomyces chromofuscus induced invagination of the cells in parallel with hydrolysis of the PC. The action of the latter group of PLases on the membrane morphology was counteracted by PLase A2, and vice versa. Thus, participation of the membrane lipid bilayer in the induction of membrane conformational change and hence cell shape change was demonstrated.
...
PMID:Asymmetric manipulation of the membrane lipid bilayer of intact human erythrocytes with phospholipase A, C, or D induces a change in cell shape. 52 37

The Clara cell of the bronchiole is unique to the lung; the cell's function is not clear. The localization of the lipid-hydrolase enzymes phospholipase, lysophospholipase, and lipase was examined ultrastructurally in the Clara cell of the rat bronchiole. The secretory granules of the Clara cell showed a strong reaction of lysophospholipase and a weak reaction of lipase. Phospholipase activity was not detected intracellularly. These findings suggest that the Clara cell secretes lipase-phospholipase into the bronchiolar lumen, thus catabolizing the pulmonary surfactant phospholipids.
...
PMID:Ultrastructural localization of phospholipases in the Clara cell of the rat bronchiole. 58 34

1. Sonicated glycophorin-containing vesicles of dioleoyl phosphatidylcholine have been made. The outside-inside distributions of the lipid molecules in these vesicles was measured with NMR and was found to be comparable with that of protein-free vesicles. 2. The transbilayer distribution of palmitoyl lysophosphatidylcholine in these vesicles is such that they have a significantly higher content of the lyso-compound in the inner monolayer when compared with vesicles without glycophorin. 3. Lysophosphatidylcholine, added to pre-existing glycophorin-containing vesicles, is incorporated in the outer monolayer of these vesicles. Subsequently it is able to move to the inner monolayer with an estimated half time of about 1.5 h at 4 degrees C. This was measured with 13C-NMR using [N-13CH3]lysophosphatidylcholine. 4. Treatment of co-sonicated vesicles of phosphatidylcholine and lysophosphatidylcholine containing glycophorin with the enzyme lysophospholipase results in a complete degradation of the lyso-compound. A half time of transbilayer movement of lysophosphatidylcholine during this experiment was estimated to be about 1 h at 37 degrees C.
...
PMID:Protein-mediated transbilayer movement of lysophosphatidylcholine in glycophorin-containing vesicles. 62 69

The subcellular localization of lysophospholipase activity in the human gallbladder epithelium was studied by differential and density gradient centrifugation. The highest relative specific activity was found in the microsomal fraction, although the enzyme appeared in mitochondria and lysosomes as well. The cytosol did not contain any significant lysophospholipase activity, but large amounts of enzyme were solubilized during centrifugation in sucrose gradients. These findings are discussed in relation to the distribution and properties of lysophospholipase in other cells and tissues and with regard to physiological implications. The possible relevance to the pathogenesis of aseptic cholecystitis is inferred.
...
PMID:The biochemical prerequisites for preventing pathogenic lysolecithin activity in the human gallbladder. II. Studies on the subcellular localization of lysophospholipase. 63 41


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---