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)

Dopamine transporters (DATs) are neuronal phosphoproteins that clear dopamine from the synaptic cleft. Activation of protein kinase C (PKC) and inhibition of protein phosphatases by okadaic acid (OA) increase phosphorylation of DAT and lead to concomitant reduction in DAT activity and cell surface expression. Numerous potential sites for phosphorylation are present on DAT, but the sites utilized and their relationship to transport regulation are currently unknown. We used peptide mapping and epitope-specific immunoprecipitation to identify the region of DAT that undergoes phosphorylation in rat striatal tissue. Phosphoamino acid analysis revealed that basal and stimulated samples were phosphorylated primarily on serine. Digestion of (32)PO(4)-labeled DAT with trypsin and immunoprecipitation with N- or C-terminal specific antisera failed to isolate phosphopeptide fragments corresponding to photoaffinity-labeled fragments that contain all internal interhelical loops. However, digestion of (32)PO(4)-labeled DAT with endoproteinase asp-N and immunoprecipitation with an N-terminal antiserum extracted two phosphopeptide fragments from both basal and PKC/OA-stimulated samples, demonstrating that the N-terminal cytoplasmic tail is a major site of phosphorylation. Aminopeptidase treatment of PKC- and/or OA-stimulated DAT cleaved essentially all (32)PO(4) label without proteolysis extending past transmembrane domains 1 and 2, providing further evidence that most phosphorylation sites are near the N terminus and not in intracellular loops or C-terminal domains. In situ proteolysis of the N-terminal tail indicates that the majority of stimulated phosphorylation sites are N-terminal to an antibody epitope at residues 42-59. Two-dimensional analysis of purified protein produced three tryptic phosphopeptides that may result from phosphorylation of multiple sites, but the fragments did not co-migrate with synthetic tryptic peptides phosphorylated at serines 2 and 4. These results indicate that most or all of the basal and stimulated phosphorylation of DAT in striatal tissue occurs on one or more residues in a group of six serines clustered near the distal end of the cytoplasmic N terminus.
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PMID:Dopamine transporters are phosphorylated on N-terminal serines in rat striatum. 1199 76

This work monitored changes in some digestive enzymes (trypsin and aminopeptidase) associated with the building up of resistance in Cx. pipiens larvae to two chemical insecticides (methomyl and/or malathion) and one biological insecticide (Bacillus thuringiensis-H14 or B.t H 14). The LC50 value of methomyl for both field- and the 12th generation (F12) of the selected strain was 1.789 ppm and 8.925 ppm respectively. The LC50 value of malathion for both field and the F12 of the selected strain was 0.082 ppm and 0.156 ppm respectively, and those of B.t H14 of field strain and the F12 was 2.550ppm & 2.395ppm respectively. The specific activity of trypsin enzyme in control susceptible colony was 20.806 +/- 0.452micromol/min/mg protein; but at F4 and F8 for malathion and methomyl treated larvae were 10.810 +/- 0.860 & 15.616+/-0.408 micromol/min/mg protein, respectively. Trypsin activity of F12 in treated larvae with B.t.H14 was 2.097 +/- 0.587 microiol/min/mg protein. Aminopeptidase specific activity for susceptible control larvae was 173.05 +/- 1.3111 micromol/min/mg protein. This activity decreased to 145.15 +/- 4.12, 152.497 +/- 6.775 & 102.04 +/- 3.58a micromol/min/mg protein after larval (F 12) treatment with methomyl, malathion and B.t H 14 respectively.
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PMID:Digestive enzyme as benchmark for insecticide resistance development in Culex pipiens larvae to chemical and bacteriologic insecticides. 2369 30

An analysis of the in vitro activities of proteolytic enzymes from cotyledons of germinating cucumber seeds has been carried out and the effects of protein degradation products on such activities monitored. Aminopeptidase activity is substantially inhibited with either L-leucine or L-phenylalanine and trypsin activity with L-arginine. Aminopeptidase activity was also markedly reduced in the presence of individual di- and tripeptides. Of the peptides tested, however, only L-tryptophyl-L-phenylalanine inhibited the degradation of native cucumber seed protein by the endogenous cucumber seed protease(s) (autodigestive activity).
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PMID:The control of food mobilization in seeds of Cucumis sativus L. : III. The control of protein degradation. 2430 1

Since European sea bass (Dicentrarchus labrax) larvae occurred in coastal and estuarine waters at early life stages, they are likely to be exposed to reduced dissolved oxygen waters at a sensitive developmental stage. However, the effects of hypoxia at larval stage, which depend in part on fish species, remain very poorly documented in European sea bass. In the present study, the impacts of an experimental exposure to a chronic moderate hypoxia (40 % air saturation) between 30 and 38 days post-hatching on the physiological and developmental traits of European sea bass larvae were assessed. This study was based on the investigation of survival and growth rates, parameters related to energy metabolism [Citrate Synthase (CS) and Cytochrome-c Oxidase (COX) activities], and biological indicators of the maturation of digestive function [pancreatic (trypsin, amylase) and intestinal (Alkaline Phosphatase "AP" and Aminopeptidase-N "N-LAP") enzymes activities]. While condition of hypoxia exposure did not induce any significant mortality event, lower growth rate as well as CS/COX activity ratio was observed in the Hypoxia Treatment group. In parallel, intestinal enzyme activities were also lower under hypoxia. Altogether, the present data suggest that sea bass larvae cope with moderate hypoxia by (1) reducing processes that are costly in energy and (2) regulating mitochondria functions in order to respond to energy-demand conditions. Both these effects are associated with a delay in the maturation of the digestive function.
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PMID:Exposure to chronic moderate hypoxia impacts physiological and developmental traits of European sea bass (Dicentrarchus labrax) larvae. 2548 12

Proteins constitute a particularly bioavailable subset of organic carbon and nitrogen in aquatic environments but must be hydrolyzed by extracellular enzymes prior to being metabolized by microorganisms. Activities of extracellular peptidases (protein-degrading enzymes) have frequently been assayed in freshwater systems, but such studies have been limited to substrates for a single enzyme [leucyl aminopeptidase (Leu-AP)] out of more than 300 biochemically recognized peptidases. Here, we report kinetic measurements of extracellular hydrolysis of five substrates in 28 freshwater bodies in the Delaware Water Gap National Recreation Area in the Pocono Mountains (PA, United States) and near Knoxville (TN, United States), between 2013 and 2016. The assays putatively test for four aminopeptidases (arginyl aminopeptidase, glyclyl aminopeptidase, Leu-AP, and pyroglutamyl aminopeptidase), which cleave N-terminal amino acids from proteins, and trypsin, an endopeptidase, which cleaves proteins mid-chain. Aminopeptidase and the trypsin-like activity were observed in all water bodies, indicating that a diverse set of peptidases is typical in freshwater. However, ratios of peptidase activities were variable among sites: aminopeptidases dominated at some sites and trypsin-like activity at others. At a given site, the ratios remained fairly consistent over time, indicating that they are driven by ecological factors. Studies in which only Leu-AP activity is measured may underestimate the total peptidolytic capacity of an environment, due to the variable contribution of endopeptidases.
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PMID:Potential Activities of Freshwater Exo- and Endo-Acting Extracellular Peptidases in East Tennessee and the Pocono Mountains. 2955 61

Wild relatives of crops are an important source of resistance genes against insect pests. However, it is important to identify the accessions of wild relatives with different mechanisms of resistance to broaden the basis and increase the levels of resistance to insect pests. Therefore, we evaluated 15 accessions of wild relatives of chickpea belonging to seven species and five genotypes of cultivated chickpea for their resistance to pod borer, Helicoverpa armigera, which is the most damaging pest of chickpea. The test genotypes were evaluated for resistance to H. armigera using detached pod assay. Data were also recorded on activity of the digestive enzymes in the midgut of the larvae fed on different wild relatives of chickpea. All the wild chickpea genotypes suffered lower pod damage and weight gained by the third-instar larvae of H. armigera was lower when fed on them compared with the cultivated chickpea. The accessions, IG 69979 (Cicer cuneatum), PI 599066, IG 70006, IG 70018, IG 70022 (Cicer bijugum), IG 599076 (Cicer chrossanicum), and IG 72933, IG 72953 (Cicer reticulatum), showed high levels of resistance to H. armigera. There were significant differences in protease activity in larval gut of H. armigera fed on different wild relatives of chickpea. Total protease, trypsin, and chymotrypsin activities were lowest in larva fed on PI 599066 (C. bijugum) compared with that in the larvae fed IG 69979 (C. cuneatum) and IG 70022 (C. bijugum). Aminopeptidase activity was highest in the larvae fed on IG 70022 (C. bijugum) and IG 599076 (C. chrossanicum), whereas lowest activity was recorded in the larvae fed on ICC 3137 and KAK 2 (susceptible checks). The variation in protease activities may be due to the presence of protease inhibitors in the wild relatives or hyperproduction of enzymes by the larvae as result of protease inhibitor activity of the wild relatives, resulting in low weight gain by larvae. The results suggested that wild relatives of chickpea with diverse mechanisms of resistance can be exploited to increase the levels and diversify the basis of resistance to H. armigera in cultivated chickpea.
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PMID:Proteolytic Activity in the Midgut of Helicoverpa armigera (Noctuidae: Lepidoptera) Larvae Fed on Wild Relatives of Chickpea, Cicer arietinum. 2992 50

Post-translational modifications (PTMs) of histone N-terminal tails in nucleosome core particle (NCP), such as acetylation, play crucial roles in regulating gene expression. To unveil the regulation mechanism, atomic-level structural analysis of in-vitro modified NCP is effective with verifying the PTMs of histones. So far, identification of PTMs of NCP originating from living cells has mainly been performed using mass spectrometry (MS) techniques, such as bottom-up approach. The bottom-up approach is the most established method for protein characterization, but it does not always provide sufficient information on the acetylated sites of lysine residues in the histone tails if trypsin digestion is carried out. For histone proteins, which have many basic amino acids, trypsin generates too many short fragments that cannot be perfectly analyzed by tandem MS. In this study, we investigated the in vitro acetylation sites in the histone H3 tail using a top-down sequence analysis, matrix-assisted laser desorption/ionization in-source decay (MALDI-ISD) experiment, in combination with aminopeptidase digestion. Aminopeptidase can cleave peptide bonds one-by-one from the N-terminus of peptides or proteins, generating N-terminally truncated peptides and/or proteins. As a result, it was identified that this method enables sequence characterization of the entire region of the H3 tail. Also, application of this method to H3 in in-vitro acetylated NCP enabled assigning acetylation sites of H3. Thus, this method was found to be effective for obtaining information on in-vitro acetylation of NCP for structural biology study.
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PMID:Mass Spectrometric Characterization of Histone H3 Isolated from in-Vitro Reconstituted and Acetylated Nucleosome Core Particle. 3322 99


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