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

Two types of phospholipase B of Penicillium notatum, the native type and the modified type that is thought to be generated by the introduction of some nicks into the native type of enzyme by the endogenous protease(s), were distinguished on a slab sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis under a nonreducing condition. The native form migrated with a rate corresponding to 95K Da, whereas the modified form migrated more slowly, corresponding to 106K Da, presumably because of its more extended conformation. That the "106K" protein was indeed a nicked product of the "95K" protein was confirmed by amino acid analysis, peptide mapping, N- and C-terminal sequence analyses, and immunoblotting. The peptide fragments (70K and 37K + 32K) comprising the modified protein were isolated by gel filtration in the presence of SDS and 2-mercaptoethanol (the 32K peptide was suggested to be a partial proteolytic product of the 37K peptide). When the "95K" protein was subjected to the same treatment under denaturing condition, it retained a low, but significant, enzymatic activity; in contrast, the separated peptide fragments did not show any significant activity. By a coincubation of these fragments, however, a restoration of enzymatic activity was observed through a reformation of the active complex, corresponding to the original modified protein. The enzymatic activity of this complex was further increased by a treatment with guanidine X HCl, followed by dialysis. The association of peptide fragments appears to occur through the formation of interpeptidal disulfide bonds.
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PMID:Molecular relationship between two types of phospholipase B from Penicillium notatum and reconstitution of active enzyme from its peptide fragments. 354 77

Phospholipase B bound tightly to the membrane fraction of baker's yeast (Saccharomyces cerevisiae) was purified approximately 226-fold by extraction with sodium deoxycholate (DOC), acetone precipitation, ammonium sulfate fractionation, and column chromatographies on Phenyl-Sepharose CL-4B, DEAE-Sepharose CL-6B, and Sepharose 4B. Only one major activity peak with an apparent molecular weight of 330,000 was detected by gel filtration on Sepharose 4B. However, two glycoprotein bands, one major and one minor, were evident on SDS-polyacrylamide gel electrophoresis in the absence of 2-mercaptoethanol. Isoelectric focusing also revealed two activities, pI 3.4 (major) and pI 3.0 (minor). The purified enzyme had phospholipase B activity (in the presence of DOC) and lysophospholipase activity in a ratio of 1:4.8. Both activities had an optimum pH of 3.5-4.0. Phospholipase B activity was appreciably stimulated only by DOC among bile acids, but lysophospholipase activity was markedly inhibited by them. Both activities were not stimulated by Ca2+ and inhibited by SDS, Triton X-100, Fe3+ and Al3+. The purified enzyme hydrolyzed the acyl ester bonds of phosphatidylcholine sequentially, first the 2-acyl and then the 1-acyl groups. It preferentially hydrolyzed 1-acyl-sn-glycero-3-phosphocholine and, to a lesser degree, 2-acyl-sn-glycero-3-phosphocholine.
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PMID:Purification and properties of a membrane-bound phospholipase B from baker's yeast (Saccharomyces cerevisiae). 636 32