Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.5 (neuropathy target esterase)
 1,070 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Detergent-resistant phospholipase A, which is tightly bound to the outer membranes of Escherichia coli K-12 cells, was purified approximately 2000-fold to near homogeneity by solubilization with sodium dodecylsulfate and butan-1-ol, acid precipitation, acetone fractionation and column chromatographies on Sephadex G-100 in the presence of sodium dodecylsulfate and on DEAE-cellulose in the presence of Triton X-100. The final preparation showed a single band in the sodium dodecylsulfate gel system. The enzyme hydrolyzes both the 1-acyl and 2-acyl chains of phosphatidylethanolamine or phosphatidylcholine. It also attacks 1-acyl and 2-acylglycerylphosphorylethanolamine. Thus, this enzyme shows not only phospholipase A1 and lysophospholipase L1 activities but also phospholipase A2 and lysophospholipase L2 activities. The enzyme lost its activity completely on incubation at 80 degrees C for 5 min at either pH 6.4 or pH 8.0. It was stable in 0.5% sodium dodecylsulfate at below 40 degrees C. The enzyme was inactivated on incubation for 5 min at 90 degrees C in 1% sodium dodecylsulfate/1% 2-mercaptoethanol/4 M urea. The native and inactivated enzymes showed different protein bands with RF values corresponding to Mr 21 000 and Mr 28 000 respectively, in a sodium dodecylsulfate gel system. Triton X-100 seemed to protect the enzyme from inactivation. The purified enzyme was fully active on phosphatidylethanolamine in the presence of 0.0002% or 0.05% Triton X-100. The enzyme requires Ca2+. From its properties this enzyme seems to be identical with the enzyme purified from crude extracts of Escherichia coli B by Scandella and Kornberg. However, it differs from the latter in its positional specificity and susceptibility to sodium dodecylsulfate. Possible explanation of the difference of positional specificity of the two preparations is also described.
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PMID:Detergent-resistant phospholipase A of Escherichia coli K-12. Purification and properties. 1 2

Human preimplantation embryos and endometrium secrete platelet-activating factor (PAF). The mechanism of phosphatidylcholine (PC) degradation stimulated by PAF was investigated in endometrial explants prelabeled with [methyl-3H]choline or preincubated with [3H]butan-1-ol. Analysis of the water-soluble metabolites of PAF-induced PC hydrolysis in secretory endometrium demonstrated that the stimulated generation of [3H]choline ([3H]Cho) precedes that of [3H]choline phosphate ([3H]ChoP) and [3H]glycerophosphocholine ([3H]GPC). Within 30 sec there was a rapid rise in PAF-induced [3H]Cho generation and by 2 min this had increased to 59.9% +/- 10.6% (p less than 0.02), with no effect upon [3H]ChoP and [3H]GPC during this period. Both [3H]GPC and [3H]ChoP, however, were increased at a later time point. The slower [3H]ChoP generation may suggest that PC-specific phospholipase C activation as well as delayed [3H]GPC rise may be due to PC-specific phospholipase A2 and lysophospholipase activation. Phospholipase D activity was confirmed by the incorporation of high-specific-activity [3H]butan-1-ol into [3H]phosphatidylbutanol ([3H]PBut). The rapid generation of [3H]PBut, which paralleled the rise in intracellular [3H]Cho, strongly suggests that PC breakdown is catalyzed by the phospholipase D pathway. It is proposed that PAF induces PC hydrolysis as a consequence of an early phospholipase D-catalyzed breakdown of PC in human secretory endometrium. This may be an alternative source for prostaglandin synthesis and an important pathway essential for long-term activation of local cellular events at the time of implantation.
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PMID:Platelet-activating factor mediates phosphatidylcholine hydrolysis by phospholipase D in human endometrium. 163 48

In present study, lysophospholipase C (lysoPLC) was purified from homogenate of pig brain. LysoPLC was purified from brain membranes by procedures employing acetic acid precipitation, 1-butanol solubilization and ammonium sulfate fractionation, and chromatographies. In SDS-PAGE, the purified enzyme protein was relatively homogeneous with molecular mass of around 65 kDa. The lysoPLC activity possesses an optimal pH of 8.5, and Km and Vm values of 120.3 microM, and 141.6 micromole/h/mg protein, respectively for 1-lauroyl lysophosphatidylcholine(LPC), and 72.4 microM and 89.8 micromole/h/mg protein for glycerophosphorylcholine (GPC). In thermal denaturation at 60 degrees C, the enzyme expressed the same inactivation pattern in the hydrolysis of 1-lauroyl LPC and GPC. In the structure activity relationship, catalytic efficacy (Vm/Km value) was the greatest for 1-docosahexaenoyl LPC, followed by 1-arachidonoyl LPC, GPC, 1-hexanoyl LPC, 1-lauroyl LPC, 1-linoleoyl LPC, 1-myristoyl LPC and 1-oleoyl LPC. Metal ion requirement indicates that Zn(2+) was crucial for lysoPLC activity. Noteworthy, in the inhibition by oxyanions, the enzyme was selectively and noncompetitively inhibited by tellurite ions with Ki value of 0.16 and 0.18 microM in hydrolyzing 1-lauroyl LPC and GPC, respectively. Taken together, it is suggested that lysoPLC, possessing broad substrate specificity, may be implicated in the supply of phosphocholine in brain tissue.
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PMID:Purification and characterization of lysophospholipase C from pig brain. 1958 46