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  1. AU="Enríquez, Paula"
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  1. Artikel: Habitat-Use Patterns among Migrant and Resident Landbirds of Contrasting Dietary Habits in a Southern Mexican Wetland

    Ruiz, Mateo D. M / León-Cortés, Jorge L / Enríquez, Paula L / García-Estrada, Carlos / Salazar, José Luis Rangel

    Ardeola. 2019 May 2, v. 66, no. 2

    2019  

    Abstract: The distribution of resident and migratory bird abundance across mangrove and marsh patches can produce dynamic and guild-specific habitat-use patterns. Using 32 consecutive months of point counts in a coastal landscape in Oaxaca, Mexico, we studied the ... ...

    Titelübersetzung Patrones de Uso Del Hábitat Entre Aves Terrestres Migratorias Y Residentes de Hábitos Alimentarios Contrastantes En Un Humedal Del Sur de México
    Abstract The distribution of resident and migratory bird abundance across mangrove and marsh patches can produce dynamic and guild-specific habitat-use patterns. Using 32 consecutive months of point counts in a coastal landscape in Oaxaca, Mexico, we studied the annual cycle, non-breeding season (October to March) and breeding season (May to August) of terrestrial birds. For broad trophic guilds of plant-consumers and insectivores, we disclosed seasonal dynamics and assessed the spread of non-breeding season abundance across migratory habit categories and habitat types. To test for habitat-use patterns derived from hypotheses concerning specific trophic resources, we focused on subsets within trophic guilds: frugivores (plant-consumers that mainly eat fruit) and invertebrate gleaners (insectivores that mainly eat terrestrial leaf and stem invertebrates). Drawing on a resourcecentred dietary requirement hypothesis, we predicted lower abundance of migrant frugivores in mangrove, where palatable fruit availability was expected to be low and resident frugivores probably exploited invertebrates to feed nestlings. Based on the competition-oriented nest predation hypothesis, we anticipated a higher proportion of migrant invertebrate gleaners in marsh. We recorded migrant birds in every month of the year. For 20 plant-consumer species, the non-breeding season density was highest among residents in mangrove (> 5 individuals per hectare). For 46 insectivore species, densities were > 5 and > 9 individuals per hectare for migrants and residents, respectively. Comparable average abundances in trophic guilds suggested both migrant and resident species were equally important. For 14 frugivore species, a higher proportion of migrants in marsh (0.90) than mangrove (0.03) resulted from reciprocal between-habitat changes in migrant and resident abundances, as predicted by the dietary requirement hypothesis. For 22 invertebrate gleaners, proportions of migrants in mangrove (0.45) and marsh (0.55) were comparable, as were abundances. Contrary to the nest predation hypothesis, any between-habitat variation in invertebrate gleaner nesting activity did not markedly influence non-breeding season abundance. —Ruiz, M.D.M., León-Cortés, J.L., Enríquez, P.L., García-Estrada, C. & Rangel Salazar, J.L. (2019). Habitat-use patterns among migrant and resident landbirds of contrasting dietary habits in a southern Mexican wetland. Ardeola, 66: 291-310.
    Schlagwörter breeding season ; eating habits ; frugivores ; fruit consumption ; fruits ; habitat preferences ; habitats ; insectivores ; invertebrates ; landscapes ; leaves ; marshes ; migratory behavior ; migratory birds ; nesting ; nestlings ; nests ; nutrient requirements ; predation ; Mexico
    Sprache Englisch
    Erscheinungsverlauf 2019-0502
    Umfang p. 291-310.
    Erscheinungsort Spanish Society of Ornithology
    Dokumenttyp Artikel
    ZDB-ID 2196653-9
    ISSN 2341-0825 ; 0570-7358
    ISSN (online) 2341-0825
    ISSN 0570-7358
    DOI 10.13157/arla.66.2.2019.ra3
    Datenquelle NAL Katalog (AGRICOLA)

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  2. Artikel: Pollination syndromes and interaction networks in hummingbird assemblages in El Triunfo Biosphere Reserve, Chiapas, Mexico

    Partida-Lara, Ruth / Enríquez, Paula L / Vázquez-Pérez, José Raúl / de Bonilla, Esteban Pineda-Diez / Martínez-Ico, Miguel / Rangel-Salazar, José L

    Journal of tropical ecology. 2018, v. 34, no. 5

    2018  

    Abstract: Plant–animal mutualistic interactions through ecological network systems and the environmental conditions in which they occur, allow us to understand patterns of species composition and the structure and dynamics of communities. We evaluated whether ... ...

    Abstract Plant–animal mutualistic interactions through ecological network systems and the environmental conditions in which they occur, allow us to understand patterns of species composition and the structure and dynamics of communities. We evaluated whether flower morphologies with different pollination syndromes (ornithophilous and non-ornithophilous) are used by hummingbirds and whether these characteristics affect the structure (core-peripheral species) of hummingbird networks. Observations were made in flowering patches, where plant–hummingbird interactions were recorded at three altitudes (300–2500 m) during three seasons (dry, rainy and post-rainy) from 2015 to 2016 at El Triunfo Biosphere Reserve, Chiapas, Mexico. We recorded 15 hummingbird species interacting with 58 plant species, and the greatest number of interacting hummingbird species (11; 14) and plant species (28; 40) were found at middle altitudes and during the dry season, respectively. In all study sites, most of the plant species visited by hummingbirds had an ornithophilous syndrome (67%) at high altitudes (22 plant species) and during the dry season (26 plant species), but more individual hummingbirds visited non-ornithophilous plant species. The hummingbird species at high altitudes exhibited the greatest level of specialization towards plants (H2′ = 0.74), but the networks of plant-hummingbird interactions were generalist (H2′ = 0.25); i.e. visiting plants with both syndromes, at low altitudes. The core generalist hummingbird species remained constant with altitude and season, but the core generalist plant species varied between different altitudes and seasons according to the phenology of the species.
    Schlagwörter altitude ; bird pollination ; conservation areas ; dry season ; flowers ; hummingbirds ; phenology ; species diversity ; Mexico
    Sprache Englisch
    Umfang p. 293-307.
    Erscheinungsort Cambridge University Press
    Dokumenttyp Artikel
    Anmerkung NAL-AP-2-clean
    ZDB-ID 395518-7
    ISSN 1469-7831 ; 0266-4674
    ISSN (online) 1469-7831
    ISSN 0266-4674
    DOI 10.1017/S0266467418000263
    Datenquelle NAL Katalog (AGRICOLA)

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  3. Artikel ; Online: Organochlorine Pesticides in the Ferruginous Pygmy Owl (Glaucidium brasilianum) in Chiapas, Mexico.

    Arrona-Rivera, Alicia E / Enríquez, Paula L / García-Feria, Luis M / Orellana, Sergio Alvarado / von Osten, Jaime Rendón

    Bulletin of environmental contamination and toxicology

    2016  Band 97, Heft 3, Seite(n) 337–345

    Abstract: Concentrations of organochlorine pesticides were quantified in samples of feathers (n = 17) and blood (n = 15) of the ferruginous pygmy owl (Glaucidium brasilianum). The individuals were captured near the Protected Natural Area Cerro Sonsonate, Chiapas, ... ...

    Abstract Concentrations of organochlorine pesticides were quantified in samples of feathers (n = 17) and blood (n = 15) of the ferruginous pygmy owl (Glaucidium brasilianum). The individuals were captured near the Protected Natural Area Cerro Sonsonate, Chiapas, Mexico, between February and June 2014. In both tissues, pesticides belonging to seven organochlorine chemical families were detected. However, the organochlorine pesticide concentrations differed between feathers and blood. The highest concentrations of hexachlorocyclohexanes were found in feathers (0.63 ± 0.89 μg/g), whereas the highest concentrations of ΣDrines were found in blood (0.31 ± 0.47 μg/mL). By using the summed concentrations for each of the seven families of pesticides found in feathers, we did not find any significant correlation between the pesticides and pectoral muscle or body weight (p > 0.15). The ΣDDT group was the only pesticide family that showed a positive correlation with owl body weight (r = 0.60, p = 0.05); the concentrations of these pesticides were also high in feather and blood tissues (r = 0.87, p = 0.02). Our results confirm that ferruginous pygmy owls in the study area are exposed to these pesticides.
    Mesh-Begriff(e) Animals ; Environmental Monitoring ; Environmental Pollutants/metabolism ; Feathers/chemistry ; Feathers/metabolism ; Hydrocarbons, Chlorinated/analysis ; Hydrocarbons, Chlorinated/metabolism ; Lindane/blood ; Lindane/metabolism ; Mexico ; Pesticides/analysis ; Pesticides/metabolism ; Strigiformes/metabolism
    Chemische Substanzen Environmental Pollutants ; Hydrocarbons, Chlorinated ; Pesticides ; Lindane (59NEE7PCAB)
    Sprache Englisch
    Erscheinungsdatum 2016-09
    Erscheinungsland United States
    Dokumenttyp Journal Article
    ZDB-ID 6895-0
    ISSN 1432-0800 ; 0007-4861
    ISSN (online) 1432-0800
    ISSN 0007-4861
    DOI 10.1007/s00128-016-1861-0
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  4. Artikel ; Online: Cultural significance of wild mammals in Mayan and mestizo communities of the Lacandon Rainforest, Chiapas, Mexico.

    García Del Valle, Yasminda / Naranjo, Eduardo J / Caballero, Javier / Martorell, Carlos / Ruan-Soto, Felipe / Enríquez, Paula L

    Journal of ethnobiology and ethnomedicine

    2015  Band 11, Seite(n) 36

    Abstract: Background: Several ethnobiology studies evaluate the cultural significance (CS) of plants and mushrooms. However, this is not the case for mammals. It is important to make studies of CS allowing the comparison of cultural groups because the value given ...

    Abstract Background: Several ethnobiology studies evaluate the cultural significance (CS) of plants and mushrooms. However, this is not the case for mammals. It is important to make studies of CS allowing the comparison of cultural groups because the value given to groups of organisms may be based on different criteria. Such information would be valuable for wildlife preservation plans. In this study, the most culturally significant species of mammals from the Lacandon Rainforest (Chiapas, Mexico) for people from two Mayan-Lacandon and mestizo communities were identified. The reasons behind the CS of the studied species were explored and the existence of differences among the cultural groups was evaluated.
    Methods: One hundred ninety-eight semi-structured and structured interviews were applied to compile socio-demographic information, qualitative data on CS categories, and free listings. Frequency of mention was a relative indicator to evaluate the CS of each species of mammal. Comparison of responses between communities was carried out through multivariate analyses. The non-parametric Mann-Whitney U test was used to compare the number of mentioned species by Lacandons and mestizos as well as different responses in the qualitative categories. A χ2 test was used to compare frequency of categories.
    Results: 38 wild mammal species were identified. The classification and Principal Components Analyses show an apparent separation between Lacandon and mestizo sites based on the relative importance of species. All four communities mentioned the lowland paca the most, followed by peccary, white-tailed deer, armadillo, and jaguar. No significant difference was found in the number of mentioned species between the two groups. Eight CS categories were identified. The most important category was "harmful mammals", which included 28 species. Other relevant categories were edible, medicinal, and appearing in narratives.
    Conclusions: The data obtained in this study demonstrates the existence of differential cultural patterns in the relationships that Lacandon and mestizo groups establish with mammals. Species are deemed important either because they are eaten of because of the harm they cause. We suggest the incorporation of local conceptions about wild animals in conservation frameworks for the fauna in the Lacandon Rainforest.
    Mesh-Begriff(e) Animals ; Animals, Wild ; Culture ; Ethnicity ; Humans ; Indians, North American/ethnology ; Interviews as Topic ; Mexico ; Rainforest
    Sprache Englisch
    Erscheinungsdatum 2015-05-07
    Erscheinungsland England
    Dokumenttyp Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2202544-3
    ISSN 1746-4269 ; 1746-4269
    ISSN (online) 1746-4269
    ISSN 1746-4269
    DOI 10.1186/s13002-015-0021-7
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  5. Artikel: Abundancia de colibríes y uso de flores en un bosque templado del sureste de México.

    Partida Lara, Ruth / Enríquez, Paula L / Rangel-Salazar, José Luis / Lara, Carlos / Martínez Ico, Miguel

    Revista de biologia tropical

    2012  Band 60, Heft 4, Seite(n) 1621–1630

    Abstract: Hummingbird abundance varies with plant bloom phenology used for feeding. However, the information on hummingbird-flower interaction is limited for tropical mountain environments. We evaluated hummingbird abundance using mist nest and estimated monthly ... ...

    Titelübersetzung Hummingbird abundance and flowers use in a template forest from Southeast Mexico.
    Abstract Hummingbird abundance varies with plant bloom phenology used for feeding. However, the information on hummingbird-flower interaction is limited for tropical mountain environments. We evaluated hummingbird abundance using mist nest and estimated monthly flowering phenology visited by hummingbirds in three different habitats (oak forest, cloud forest and bush) from January to August 2010 in Huitepec Ecological Reserve. We recorded four hummingbird species (Hylocharis leucotis, Lampornis amethystinus, Lamprolaima rhami and Eugenes fulgens), and their abundance varied among habitats (H3.8=14.8, p=0.001). Seven plant species were visited for hummingbirds and showed the highest number of flower species during dry season. Bush had the highest blossom. Fuchsia paniculata had the highest blossom period but only was visited by H. leucotis. Passiflora membranacea was the only species visited for all hummingbird species. The only positive association was E. fulgens abundance with P.a membranacea bloom (r(S)=0.93, p=0.02). Hummingbird abundance fluctuations in this study are determined for interactions with floral resources and their habitat distribution.
    Mesh-Begriff(e) Animals ; Birds/classification ; Birds/physiology ; Ecosystem ; Feeding Behavior/physiology ; Flowers/classification ; Mexico ; Population Density ; Population Dynamics ; Seasons
    Sprache Spanisch
    Erscheinungsdatum 2012-12
    Erscheinungsland Costa Rica
    Dokumenttyp English Abstract ; Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2020929-0
    ISSN 2215-2075 ; 0034-7744
    ISSN (online) 2215-2075
    ISSN 0034-7744
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  6. Artikel ; Online: Underlying and proximate drivers of biodiversity changes in Mesoamerican biosphere reserves.

    Auliz-Ortiz, Daniel Martín / Benítez-Malvido, Julieta / Arroyo-Rodríguez, Víctor / Dirzo, Rodolfo / Pérez-Farrera, Miguel Ángel / Luna-Reyes, Roberto / Mendoza, Eduardo / Álvarez-Añorve, Mariana Yólotl / Álvarez-Sánchez, Javier / Arias-Ataide, Dulce María / Ávila-Cabadilla, Luis Daniel / Botello, Francisco / Braasch, Marco / Casas, Alejandro / Campos-Villanueva, Delfino Álvaro / Cedeño-Vázquez, José Rogelio / Chávez-Tovar, José Cuauhtémoc / Coates, Rosamond / Dechnik-Vázquez, Yanus /
    Del Coro Arizmendi, María / Dias, Pedro Américo / Dorado, Oscar / Enríquez, Paula / Escalona-Segura, Griselda / Farías-González, Verónica / Favila, Mario E / García, Andrés / García-Morales, Leccinum Jesús / Gavito-Pérez, Fernando / Gómez-Domínguez, Héctor / González-García, Fernando / González-Zamora, Arturo / Cuevas-Guzmán, Ramón / Haro-Belchez, Enrique / Hernández-Huerta, Arturo Heriberto / Hernández-Ordoñez, Omar / Horváth, Anna / Ibarra-Manríquez, Guillermo / Lavín-Murcio, Pablo Antonio / Lira-Saade, Rafael / López-Díaz, Karime / MacSwiney G, M Cristina / Mandujano, Salvador / Martínez-Camilo, Rubén / Martínez-Ávalos, José Guadalupe / Martínez-Meléndez, Nayely / Monroy-Ojeda, Alan / Mora, Francisco / Mora-Olivo, Arturo / Muench, Carlos / Peña-Mondragón, Juan L / Percino-Daniel, Ruth / Ramírez-Marcial, Neptalí / Reyna-Hurtado, Rafael / Rodríguez-Ruíz, Erick Rubén / Sánchez-Cordero, Víctor / Suazo-Ortuño, Ireri / Terán-Juárez, Sergio Alejandro / Valdivieso-Pérez, Ingrid Abril / Valencia, Vivian / Valenzuela-Galván, David / Vargas-Contreras, Jorge Albino / Vázquez-Pérez, José Raúl / Vega-Rivera, Jorge Humberto / Venegas-Barrera, Crystian Sadiel / Martínez-Ramos, Miguel

    Proceedings of the National Academy of Sciences of the United States of America

    2024  Band 121, Heft 6, Seite(n) e2305944121

    Abstract: Protected areas are of paramount relevance to conserving wildlife and ecosystem contributions to people. Yet, their conservation success is increasingly threatened by human activities including habitat loss, climate change, pollution, and species ... ...

    Abstract Protected areas are of paramount relevance to conserving wildlife and ecosystem contributions to people. Yet, their conservation success is increasingly threatened by human activities including habitat loss, climate change, pollution, and species overexploitation. Thus, understanding the underlying and proximate drivers of anthropogenic threats is urgently needed to improve protected areas' effectiveness, especially in the biodiversity-rich tropics. We addressed this issue by analyzing expert-provided data on long-term biodiversity change (last three decades) over 14 biosphere reserves from the Mesoamerican Biodiversity Hotspot. Using multivariate analyses and structural equation modeling, we tested the influence of major socioeconomic drivers (demographic, economic, and political factors), spatial indicators of human activities (agriculture expansion and road extension), and forest landscape modifications (forest loss and isolation) as drivers of biodiversity change. We uncovered a significant proliferation of disturbance-tolerant guilds and the loss or decline of disturbance-sensitive guilds within reserves causing a "winner and loser" species replacement over time. Guild change was directly related to forest spatial changes promoted by the expansion of agriculture and roads within reserves. High human population density and low nonfarming occupation were identified as the main underlying drivers of biodiversity change. Our findings suggest that to mitigate anthropogenic threats to biodiversity within biosphere reserves, fostering human population well-being via sustainable, nonfarming livelihood opportunities around reserves is imperative.
    Mesh-Begriff(e) Humans ; Animals ; Ecosystem ; Biodiversity ; Agriculture ; Animals, Wild ; Climate Change
    Sprache Englisch
    Erscheinungsdatum 2024-01-22
    Erscheinungsland United States
    Dokumenttyp Journal Article
    ZDB-ID 209104-5
    ISSN 1091-6490 ; 0027-8424
    ISSN (online) 1091-6490
    ISSN 0027-8424
    DOI 10.1073/pnas.2305944121
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  7. Artikel: CracidMex1: a comprehensive database of global occurrences of cracids (Aves, Galliformes) with distribution in Mexico.

    Pinilla-Buitrago, Gonzalo / Martínez-Morales, Miguel Angel / González-García, Fernando / Enríquez, Paula L / Rangel-Salazar, José Luis / Romero, Carlos Alberto Guichard / Navarro-Sigüenza, Adolfo G / Monterrubio-Rico, Tiberio César / Escalona-Segura, Griselda

    ZooKeys

    2014  , Heft 420, Seite(n) 87–115

    Abstract: Cracids are among the most vulnerable groups of Neotropical birds. Almost half of the species of this family are included in a conservation risk category. Twelve taxa occur in Mexico, six of which are considered at risk at national level and two are ... ...

    Abstract Cracids are among the most vulnerable groups of Neotropical birds. Almost half of the species of this family are included in a conservation risk category. Twelve taxa occur in Mexico, six of which are considered at risk at national level and two are globally endangered. Therefore, it is imperative that high quality, comprehensive, and high-resolution spatial data on the occurrence of these taxa are made available as a valuable tool in the process of defining appropriate management strategies for conservation at a local and global level. We constructed the CracidMex1 database by collating global records of all cracid taxa that occur in Mexico from available electronic databases, museum specimens, publications, "grey literature", and unpublished records. We generated a database with 23,896 clean, validated, and standardized geographic records. Database quality control was an iterative process that commenced with the consolidation and elimination of duplicate records, followed by the geo-referencing of records when necessary, and their taxonomic and geographic validation using GIS tools and expert knowledge. We followed the geo-referencing protocol proposed by the Mexican National Commission for the Use and Conservation of Biodiversity. We could not estimate the geographic coordinates of 981 records due to inconsistencies or lack of sufficient information in the description of the locality. Given that current records for most of the taxa have some degree of distributional bias, with redundancies at different spatial scales, the CracidMex1 database has allowed us to detect areas where more sampling effort is required to have a better representation of the global spatial occurrence of these cracids. We also found that particular attention needs to be given to taxa identification in those areas where congeners or conspecifics co-occur in order to avoid taxonomic uncertainty. The construction of the CracidMex1 database represents the first comprehensive research effort to compile current, available global geographic records for a group of cracids. The database can now be improved by continuous revision and addition of new records. The CracidMex1 database will provide high quality input data that could be used to generate species distribution models, to assess temporal changes in species distributions, to identify priority areas for research and conservation, and in the definition of management strategies for this bird group. This compilation exercise could be replicated for other cracid groups or regions to attain a better knowledge of the global occurrences of the species in this vulnerable bird family.
    Sprache Englisch
    Erscheinungsdatum 2014-06-25
    Erscheinungsland Bulgaria
    Dokumenttyp Journal Article
    ZDB-ID 2445640-8
    ISSN 1313-2970 ; 1313-2989
    ISSN (online) 1313-2970
    ISSN 1313-2989
    DOI 10.3897/zookeys.420.7050
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  8. Artikel: Insights into the interaction of human arginase II with substrate and manganese ions by site-directed mutagenesis and kinetic studies. Alteration of substrate specificity by replacement of Asn149 with Asp.

    López, Vasthi / Alarcón, Ricardo / Orellana, María S / Enríquez, Paula / Uribe, Elena / Martínez, José / Carvajal, Nelson

    The FEBS journal

    2004  Band 272, Heft 17, Seite(n) 4540–4548

    Abstract: To examine the interaction of human arginase II (EC 3.5.3.1) with substrate and manganese ions, the His120Asn, His145Asn and Asn149Asp mutations were introduced separately. About 53% and 95% of wild-type arginase activity were expressed by fully ... ...

    Abstract To examine the interaction of human arginase II (EC 3.5.3.1) with substrate and manganese ions, the His120Asn, His145Asn and Asn149Asp mutations were introduced separately. About 53% and 95% of wild-type arginase activity were expressed by fully manganese activated species of the His120Asn and His145Asn variants, respectively. The K(m) for arginine (1.4-1.6 mM) was not altered and the wild-type and mutant enzymes were essentially inactive on agmatine. In contrast, the Asn149Asp mutant expressed almost undetectable activity on arginine, but significant activity on agmatine. The agmatinase activity of Asn149Asp (K(m) = 2.5 +/- 0.2 mM) was markedly resistant to inhibition by arginine. After dialysis against EDTA, the His120Asn variant was totally inactive in the absence of added Mn(2+) and contained < 0.1 Mn(2+).subunit(-1), whereas wild-type and His145Asn enzymes were half active and contained 1.1 +/- 0.1 Mn(2+).subunit(-1) and 1.3 +/- 0.1 Mn(2+).subunit(-1), respectively. Manganese reactivation of metal-free to half active species followed hyperbolic kinetics with K(d) of 1.8 +/- 0.2 x 10(-8) M for the wild-type and His145Asn enzymes and 16.2 +/- 0.5 x 10(-8) m for the His120Asn variant. Upon mutation, the chromatographic behavior, tryptophan fluorescence properties (lambda(max) = 338-339 nm) and sensitivity to thermal inactivation were not altered. The Asn149-->Asp mutation is proposed to generate a conformational change responsible for the altered substrate specificity of arginase II. We also conclude that, in contrast with arginase I, Mn(2+) (A) is the more tightly bound metal ion in arginase II.
    Mesh-Begriff(e) Amino Acid Substitution ; Arginase/genetics ; Arginase/metabolism ; Base Sequence ; DNA/genetics ; Humans ; In Vitro Techniques ; Kinetics ; Manganese/metabolism ; Mutagenesis, Site-Directed ; Recombinant Proteins/genetics ; Recombinant Proteins/metabolism ; Substrate Specificity
    Chemische Substanzen Recombinant Proteins ; Manganese (42Z2K6ZL8P) ; DNA (9007-49-2) ; ARG2 protein, human (EC 3.5.3.1) ; Arginase (EC 3.5.3.1)
    Sprache Englisch
    Erscheinungsdatum 2004-09-13
    Erscheinungsland England
    Dokumenttyp Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2173655-8
    ISSN 1742-4658 ; 1742-464X
    ISSN (online) 1742-4658
    ISSN 1742-464X
    DOI 10.1111/j.1742-4658.2005.04874.x
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  9. Artikel: Kinetic studies and site-directed mutagenesis of Escherichia coli agmatinase. A role for Glu274 in binding and correct positioning of the substrate guanidinium group.

    Carvajal, Nelson / Orellana, María S / Salas, Mónica / Enríquez, Paula / Alarcón, Ricardo / Uribe, Elena / López, Vasthi

    Archives of biochemistry and biophysics

    2004  Band 430, Heft 2, Seite(n) 185–190

    Abstract: The interaction of Escherichia coli agmatinase (EC 3.5.3.11) with the substrate guanidinium group was investigated by kinetic and site-directed mutagenesis studies. Putrescine and guanidinium ions (Gdn+) were slope-linear, competitive inhibitors with ... ...

    Abstract The interaction of Escherichia coli agmatinase (EC 3.5.3.11) with the substrate guanidinium group was investigated by kinetic and site-directed mutagenesis studies. Putrescine and guanidinium ions (Gdn+) were slope-linear, competitive inhibitors with respect to agmatine and their bindings to the enzyme were not mutually exclusive. By site-directed mutagenesis, the E274A variant exhibiting about 1-2% of wild-type activity was obtained. Mutation produced a moderate, but significant, increase in the Km value for agmatine (from 1.1 +/- 0.2 mM to 6.3 +/- 0.3 mM) and the Ki value for competitive inhibition by Gdn+ (from 15.0 +/- 0.1 mM to 44.2 +/- 2.1 mM), but the Ki value for putrescine inhibition (2.8 +/- 0.2 mM) was not altered. The tryptophan fluorescence properties (lambdamax = 342 nm) and circular dichroism spectra were not significantly altered by the Glu274 --> Ala mutation. The dimeric structure of the enzyme was also maintained. We conclude that Glu274 is involved in binding and positioning of the guanidinium moiety of the substrate for efficient catalysis. A kinetic mechanism involving rapid equilibrium random release of products is proposed for E. coli agmatinase.
    Mesh-Begriff(e) Binding Sites ; Catalysis ; Escherichia coli/enzymology ; Escherichia coli/genetics ; Genetic Variation ; Glutamine/chemistry ; Glutamine/genetics ; Glutamine/metabolism ; Guanidine/metabolism ; Kinetics ; Models, Molecular ; Mutagenesis, Site-Directed ; Mutation ; Structure-Activity Relationship ; Substrate Specificity ; Ureohydrolases
    Chemische Substanzen Glutamine (0RH81L854J) ; Ureohydrolases (EC 3.5.3.-) ; agmatinase (EC 3.5.3.11) ; Guanidine (JU58VJ6Y3B)
    Sprache Englisch
    Erscheinungsdatum 2004-10-15
    Erscheinungsland United States
    Dokumenttyp Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 523-x
    ISSN 1096-0384 ; 0003-9861
    ISSN (online) 1096-0384
    ISSN 0003-9861
    DOI 10.1016/j.abb.2004.07.005
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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