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

The nucleotide sequence of the pldB gene of Escherichia coli K-12, which codes for lysophospholipase L2 located in the inner membrane, was determined. The deduced amino acid sequence of lysophospholipase L2 contains 340 amino acid residues, resulting in a protein with a molecular weight of 38,934. It is characterized by a high content of arginine residues (36 out of 340 residues). The amino acid sequence near the NH2-terminus of the protein is composed of a large number of polar or charged amino acid residues, suggesting that this region cannot be a signal peptide. The hydropathy profile of the deduced amino acid sequence of lysophospholipase L2 was studied. Most of the region was rather hydrophilic, and there was no stretch of hydrophobic amino acid region, such as might be predicted to traverse the lipid bilayer. These results are consistent with the experimental observation that lysophospholipase L2 is extracted by salt solution from the membrane fraction, and it may be classified as a peripheral membrane protein. Computer analysis showed that there is no homology in amino acid sequences between lysophospholipase L2 and other extracellular phospholipases, as well as detergent-resistant phospholipase A, which is another membrane-bound phospholipase in E. coli and whose DNA sequence was determined (Homma, H., Kobayashi, T., Chiba, N., Karasawa, K., Mizushima, H., Kudo, I., Inoue, K., Ideka, H., Sekiguchi, M., & Nojima, S. (1984) J. Biochem. 96, 1655-1664). This is the first report of the primary structure of a lysophospholipase.
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PMID:Nucleotide sequence of the pldB gene and characteristics of deduced amino acid sequence of lysophospholipase L2 in Escherichia coli. 390 45

Lysophospholipase L2, which is bound to the inner membrane of Escherichia coli K-12, was produced in a large amount in cells bearing its cloned structural gene. Starting from these cells, the lysophospholipase L2 was purified approximately 700-fold to near homogeneity by solubilization with KCl, ammonium sulfate fractionation, chromatofocusing in the presence of a zwitterionic detergent, CHAPS (3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate), and heparin-Sepharose affinity column chromatography. The final preparation showed a single protein band with a molecular weight of 38,500 daltons in SDS-polyacrylamide gel electrophoresis. The amino acid sequence of the NH2-terminal portion of the purified enzyme was determined. It was in complete agreement with that deduced from the nucleotide sequence of the structural gene, pldB [Kobayashi, T., Kudo, I., Karasawa, K., Mizushima, H., Inoue, K., & Nojima, S. (1985) J. Biochem. 98, 1017-1025.] The purified enzyme hydrolyzes 2-acyl glycerophosphoethanolamine (GPE) and 2-acyl glycerophosphocholine (GPC) more effectively than 1-acyl GPE and 1-acyl GPC, but does not attack diacylphospholipids. The enzyme also catalyzes the transfer of an acyl group from lysophospholipid to phosphatidylglycerol for formation of acyl phosphatidylglycerol. The acyl group was more effectively transferred from 2-acyl lysophospholipid than from the 1-acyl derivative. This enzyme was heat-labile and was inactivated at 55 degrees C within 5 min. The present paper shows clearly that lysophospholipase L2 is a different enzyme protein from lysophospholipase L1 which was formerly purified from the supernatant of the wild strain of E. coli K-12 homogenates [Doi, O. & Nojima, S. (1975) J. Biol. Chem. 250, 5208-5214].
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PMID:Purification and characterization of lysophospholipase L2 of Escherichia coli K-12. 390 47

Using a subtractive hybridization method, we have cloned cDNAs corresponding to 10 different mRNAs which share the property of being expressed in the intestine of adult but not baby rabbits. Four could be identified as coding for previously known gene products (sucrase-isomaltase, a glutathione S-transferase, a cytochrome P450, and a long form of ferritin mRNA), while six code for previously unknown proteins. One clone, AdRab-B, codes for a protein of 1458 amino acids, including (i) a putative signal sequence at the NH2 terminus, (ii) four internal repeats, 308-346 amino acids in length, (iii) a hydrophobic stretch near the COOH terminus, which represents a potential membrane anchor, and (iv) a short hydrophilic stretch at the very COOH terminus. The corresponding protein was studied with the aid of antibodies prepared against polypeptides expressed from segments of the cDNA in Escherichia coli. The protein was shown to be proteolytically processed in the intestine (but not when expressed in COS cells) and to be targeted to the brush border membrane of the enterocytes. Finally, the protein was found to have esterase and phospholipase A/lysophospholipase activity.
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PMID:Messenger RNAs expressed in intestine of adult but not baby rabbits. Isolation of cognate cDNAs and characterization of a novel brush border protein with esterase and phospholipase activity. 850 24

A brush border membrane-associated phospholipase B/lipase was solubilized from the distal two-thirds of rat small intestine by autolysis during storage at -35 degrees C over 1 month, and then the enzyme was purified to homogeneity and characterized enzymatically and structurally. The purified enzyme exhibited broad substrate specificity including esterase, phospholipase A2, lysophospholipase, and lipase activities. SDS-gel electrophoretic and reverse-phase high performance liquid chromatographic analyses demonstrated that a single enzyme catalyzes these activities. It preferred hydrolysis at the sn-2 position of diacylphospholipid and diacylglycerol without strict stereoselectivity, whereas it apparently exhibited no positional specificity toward triacylglycerol. Diisopropyl fluorophosphate, an irreversible inhibitor of serine esterases and lipases inhibited purified enzyme. When the position of enzyme on SDS-gel electrophoresis under the non-reducing conditions was determined by assaying the activity eluted from sliced gels, brush border membrane-associated enzyme corresponded to a approximately 150-kDa protein; autolysis gave a 35-kDa product, in agreement with the results of immunoblot analysis. The purified 35-kDa enzyme consisted of a 14-kDa peptide and a glycosylated 21-kDa peptide. Their NH2-terminal amino acid sequences were determined and found in the second repeat of 161-kDa phospholipase B/lipase with 4-fold tandem repeats of approximately 38 kDa each, which we cloned and sequenced in the accompanying paper (Takemori, H., Zolotaryov, F., Ting, L., Urbain, T., Komatsubara, T., Hatano, O., Okamoto, M., and Tojo, H. (1988) J. Biol. Chem. 273, 2222-2231). These results indicate that the purified enzyme is the catalytic domain derived from the second repeat of brush border membrane-associated phospholipase B/lipase.
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PMID:Purification and characterization of a catalytic domain of rat intestinal phospholipase B/lipase associated with brush border membranes. 944 64

A cDNA encoding a rat intestinal Ca(2+)-independent phospholipase B/lipase (PLB/LIP) was cloned from an ileac mucosa cDNA library using a probe amplified by polymerase chain reaction based on the purified enzyme's sequence. PLB/LIP consists of an NH2-terminal signal peptide, four tandem repeats of about 350 amino acids each, and a hydrophobic domain near the COOH terminus. The enzyme purified previously was found to be derived from the second repeat part. To examine the function of each domain, the full-length PLB/LIP, individual repeats, and a protein lacking the COOH-terminal hydrophobic stretch were expressed in COS-7 cells. The results showed that the second repeat, but not the other repeats, had all the activities (phospholipase A2, lysophospholipase, and lipase) found in the purified natural and expressed full-length enzymes, suggesting repeat 2 is a catalytic domain. The full-length enzyme was mainly present in membrane fractions and efficiently solubilized by treatment with 1% Triton X-100, but not with phosphatidylinositol-specific phospholipase C. Deletion of the COOH-terminal hydrophobic stretch caused the secretion of > 90% of synthesized PLB/LIP into culture media. These results suggest the hydrophobic domain is not replaced by a glycosylphosphatidylinositol anchor but serves as a membrane anchor directly. A message of the full-length PLB/LIP was abundantly expressed in the ileum and also, in a smaller, but significant amount, in the esophagus and testis. Immunohistochemistry showed that PLB/LIP is localized in brush border membranes of the absorptive cells, Paneth cells, and acrosomes of spermatid, suggesting its roles related and unrelated to intestinal digestion.
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PMID:Identification of functional domains of rat intestinal phospholipase B/lipase. Its cDNA cloning, expression, and tissue distribution. 944 65

We show that Legionella pneumophila possesses lysophospholipase A activity, which releases fatty acids from lysophosphatidylcholine. The NH2-terminal sequence of the enzyme contained FGDSLS, corresponding to a catalytic domain in a recently described group of lipolytic enzymes. Culture supernatants of a L. pneumophila pilD mutant lost the ability to cleave lysophosphatidylcholine.
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PMID:Novel lysophospholipase A secreted by Legionella pneumophila. 1122 14

Intestinal brush border membrane-associated phospholipase B/lipase (PLB/LIP) consists of four tandem homologous domains (repeats 1 through 4) and a COOH-terminal membrane binding domain, and repeat 2 is the catalytic domain that catalyzes phospholipase A2, lysophospholipase, and lipase activities. We examined the structural basis of the catalysis of PLB/LIP with this unique substrate specificity by site-directed mutagenesis of recombinant repeat 2 enzyme. Ser414 and Ser459 within the active serine-containing consensus sequence G-X-S-X-G in the best-established lipase family were dispensable for activity. In contrast, substitution of Ala for Ser404 almost completely inactivated the three lipolytic activities of PLB/LIP, even though the gross conformation was not altered as determined by CD spectroscopy. Notably, this Ser is located within the conserved G-D-S-L sequence on the NH2-terminal side in lipolytic enzymes of another group proposed recently. Furthermore, mutagenesis and CD spectroscopic analyses suggested that Asp518 and His659, lying within conserved short stretches in the latter group of lipolytic enzymes, were essential for activity. These three essential residues are conserved in the known PLB/LIP enzymes, suggesting that they form the catalytic triad in the active site. These results indicate that PLB/LIP represents a distinct class of the lipase family. PLB/LIP is the first mammalian member of that family. Repeat 2 is equipped with the triad, but not the other repeats, accounting for why only repeat 2 is the catalytic domain. Replacing Thr406 with Gly, matching the enzyme's sequence to the lipase consensus sequence exactly, led to a great decrease in secretion and accumulation of inactive enzyme in the cells, suggesting a role of Thr406 in the structural stability.
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PMID:Identification of essential residues for catalysis of rat intestinal phospholipase B/lipase. 1140 59