Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rickettsia prowazekii, an obligate intracellular Gram-negative bacterium, is the etiologic agent of epidemic typhus. We analyzed the proteome of the virulent Breinl strain of R. prowazekii purified from infected egg yolk sacs. Total proteins from purified R. prowazekii Breinl strain were reduced by dithiothreitol, alkylated by iodoacetic acid and digested with trypsin followed by analysis with an integrated two-dimensional liquid chromatography and mass spectrometry system (2D-LC/MS/MS). A comparison was made using previously analyzed proteome of the Madrid E strain and current analysis of the Breinl strain. For Breinl 251 proteins were identified, representing 30% of the total protein-encoding genes, using a shotgun 2D-LC/MS/MS proteomic approach. This result is identical to that of Madrid E strain. Among the identified proteins, 33 from Breinl and 37 from Madrid E have an unknown function. A methyltransferase, RP028/RP027, whose gene is mutated in the avirulent Madrid E strain but not in the virulent Breinl strain, was only detectable in the Breinl strain, consistent with the genetic mutation in Madrid E. This result suggests the possible relationship between this gene product and the virulence of the strains.
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PMID:Insight into the virulence of Rickettsia prowazekii by proteomic analysis and comparison with an avirulent strain. 1730 Oct 7

To create a metabolic sink in the jasmonic acid (JA) pathway, we generated transgenic Nicotiana attenuata lines ectopically expressing Arabidopsis (Arabidopsis thaliana) jasmonic acid O-methyltransferase (35S-jmt) and additionally silenced in other lines the N. attenuata methyl jasmonate esterase (35S-jmt/ir-mje) to reduce the deesterification of methyl jasmonate (MeJA). Basal jasmonate levels did not differ between transgenic and wild-type plants; however, after wounding and elicitation with Manduca sexta oral secretions, the bursts of JA, jasmonoyl-isoleucine (JA-Ile), and their metabolites that are normally observed in the lamina, midvein, and petiole of elicited wild-type leaves were largely absent in both transformants but replaced by a burst of endogenous MeJA that accounted for almost half of the total elicited jasmonate pools. In these plants, MeJA became a metabolic sink that affected the jasmonate metabolic network and its spread to systemic leaves, with major effects on 12-oxo-phytodieonic acid, JA, and hydroxy-JA in petioles and on JA-Ile in laminas. Alterations in the size of jasmonate pools were most obvious in systemic tissues, especially petioles. Expression of threonine deaminase and trypsin proteinase inhibitor, two JA-inducible defense genes, was strongly decreased in both transgenic lines without influencing the expression of JA biosynthesis genes that were uncoupled from the wounding and elicitation with M. sexta oral secretions-elicited JA-Ile gradient in elicited leaves. Taken together, this study provides support for a central role of the vasculature in the propagation of jasmonates and new insights into the versatile spatiotemporal characteristics of the jasmonate metabolic network.
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PMID:Ectopic expression of AtJMT in Nicotiana attenuata: creating a metabolic sink has tissue-specific consequences for the jasmonate metabolic network and silences downstream gene expression. 2175 14

A plant's inducible defenses against herbivores as well as certain developmental processes are known to be controlled by the jasmonic acid (JA) pathway. We have previously shown that ectopically expressing Arabidopsis thaliana JA O-methyltransferase in Nicotiana attenuata (35S-jmt) strongly reduces the herbivory-elicited jasmonate bursts by acting as metabolic sink that redirects free JA towards methylation; here we examine the consequences of this metabolic sink on N. attenuata's secondary metabolism and performance in nature. In the glasshouse, 35S-jmt plants produced fewer seed capsules due to shorter floral styles, which could be restored to wild type (WT) levels after hand-pollination, and were more susceptible to Manduca sexta larvae attack. When transplanted into the Great Basin Desert in Utah, 35S-jmt plants grew as well as WT empty vector, but were highly attacked by native herbivores of different feeding guilds: leaf chewers, miners, and single cell feeders. This greater susceptibility was strongly associated with reduced emissions of volatile organic compounds (hexenylesters, monoterpenes and sesquiterpenes) and profound alterations in the production of direct defenses (trypsin proteinase inhibitors [TPI], nicotine, diterpene glycosides [DTGs] and phenylpropanoid-polyamine conjugates) as revealed by a combination of targeted and metabolomics analyses of field collected samples. Complementation experiments with JA-Ile, whose formation is outcompeted in 35S-jmt plants by the methylation reaction, restored the local TPI activation to WT levels and partially complemented nicotine and DTG levels in elicited but not systemic leaves. These findings demonstrate that MeJA, the major JA metabolite in 35S-jmt plants, is not an active signal in defense activation and highlights the value of creating JA sinks to disrupt JA signaling, without interrupting the complete octadecanoid pathway, in order to investigate the regulation of plants' defense metabolism in nature.
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PMID:Diverting the flux of the JA pathway in Nicotiana attenuata compromises the plant's defense metabolism and fitness in nature and glasshouse. 2202 69

Lactoferrin (LF) is a well-known multifunctional protein. In this study, we report the inhibitory potency of bovine LF (bLF) on catechol-O-methyltransferase (COMT), which catalyzes methylation of catechol substrates. We found that bLF binds to and inhibits COMT using its N-terminal region. An N-terminal peptide fragment obtained from bLF by trypsin digestion showed a higher inhibitory activity than intact bLF. A synthetic fragment of the bLF N-terminal residues 6-50, with two pairs of disulfide bonds, also showed higher inhibitory activity than intact bLF. Enzyme kinetic studies proved that bLF did not compete with S-adenosylmethionine (the methyl donor substrate) as well as methyl acceptor substrates such as dihydroxybenzoic acid, (-)-epicatechin, norepinephrine, or l-3,4-dihydroxyphenylalanine. The inhibitory potency of bLF decreased against a COMT preparation pretreated with dithiothreitol, suggesting that the oxidation status of COMT is relevant to interaction with bLF. We further confirmed that COMT activity in the cell extracts form Caco-2 and HepG2 cells was inhibited by bLF and by the synthesized fragment. Enzyme kinetic study indicated that bLF functions as a non-competitive inhibitor by binding to an allosteric surface of COMT.
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PMID:Inhibitory Effect of Bovine Lactoferrin on Catechol-O-Methyltransferase. 2882 21


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