<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0034-7744</journal-id>
<journal-title><![CDATA[Revista de Biología Tropical]]></journal-title>
<abbrev-journal-title><![CDATA[Rev. biol. trop]]></abbrev-journal-title>
<issn>0034-7744</issn>
<publisher>
<publisher-name><![CDATA[Universidad de Costa Rica]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0034-77442017000200589</article-id>
<article-id pub-id-type="doi">10.15517/rbt.v65i2.24486</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Actividad enzimática de proteasas de Cyprinus carpio (Cypriniformes: Cyprinidae) extraídas de una laguna contaminada en México]]></article-title>
<article-title xml:lang="en"><![CDATA[Enzymatic activity of proteases from Cyprinus carpio (Cypriniformes: Cyprinidae) captured in a polluted lagoon in Mexico]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Hernández-Sámano]]></surname>
<given-names><![CDATA[Arisaí C.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Guzmán-García]]></surname>
<given-names><![CDATA[Xochitl]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[García-Barrientos]]></surname>
<given-names><![CDATA[Raquel]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Guerrero-Legarreta]]></surname>
<given-names><![CDATA[Isabel]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Universidad Autónoma Metropolitana  ]]></institution>
<addr-line><![CDATA[Ciudad de México ]]></addr-line>
<country>MX</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Universidad Politécnica de Tlaxcala  ]]></institution>
<addr-line><![CDATA[Tlaxcala ]]></addr-line>
<country>MX</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>06</month>
<year>2017</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>06</month>
<year>2017</year>
</pub-date>
<volume>65</volume>
<numero>2</numero>
<fpage>589</fpage>
<lpage>597</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.sa.cr/scielo.php?script=sci_arttext&amp;pid=S0034-77442017000200589&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.sa.cr/scielo.php?script=sci_abstract&amp;pid=S0034-77442017000200589&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.sa.cr/scielo.php?script=sci_pdf&amp;pid=S0034-77442017000200589&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[ResumenLa carpa común (Cyprinus carpio) es un organismo acuático de valor comercial que puede sobrevivir en ambientes contaminados; la carpa contiene enzimas proteolíticas de importancia fisiológica y potencial aplicación industrial. El objetivo de este estudio fue purificar parcialmente y determinar la actividad proteolítica a diferente pH de proteasas de carpas colonizando un ambiente contaminado. Se capturaron tres carpas en diferentes zonas de la laguna contaminada de Zumpango (México) a 1 m de profundidad máxima. El extracto crudo se obtuvo del músculo dorsal mediante extracción acuosa y se fraccionó con (NH4)2SO4 saturado a 20 %, 50 % y 80 %. Posteriormente, se seleccionaron las fracciones obtenidas con (NH4)2SO4 saturado a 50 % y 80 % por su alta actividad proteolítica, se concentraron por ultrafiltración con membranas de corte de peso molecular de 100 kDa, y se analizaron por electroforesis en geles de poliacrilamida con dodecil sulfato de sodio (SDS-PAGE). La actividad proteolítica del extracto crudo fue significativamente mayor (19.7-20.3 U / mg) a pH 2, 5, y 7 (P &lt; 0.001). Las fracciones obtenidas con (NH4)2SO4 saturado a 20 %, 50 % y 80 % presentaron actividades proteolíticas óptimas a pH 5 (2.8 U / mg) y pH 6 (2.2 U / mg); pH 6 (4.3 U / mg) y pH 3-4 (3.6 - 3.7 U / mg); pH 3 (10.8 U / mg) y pH 10 (10.6 U / mg); respectivamente. Las subfracciones con peso molecular &lt; 100 kDa obtenidas con (NH4)2SO4 saturado a 50 % y 80 % tuvieron máxima actividad proteolítica a pH alcalino. La subfracción &lt; 100 kDa, obtenida con (NH4)2SO4 saturado a 80 % tuvo la mayor actividad proteolítica (37.3-43.7 U / mg) a pH 8-10, factor de purificación de 3 y 19.1 % de recuperación. Trece proteínas entre 9.8 a 104.8 kDa se identificaron en el extracto proteolítico crudo. Las proteínas de 31 - 33 y 39 - 41 kDa tuvieron la concentración más alta en las fracciones estudiadas, sugiriendo la posible predominancia de serín y aspartil proteasas, respectivamente. Nosotros sugerimos que la presencia de proteasas con máxima actividad a pH alcalino está relacionada con la adaptación de C. carpio a aguas contaminadas con pH alto. Aunque estos peces son inadecuados para el consumo humano, pueden ser empleados como materia prima para la producción de proteasas destinadas para varias industrias, incluido el tratamiento de aguas residuales.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[AbstractCommon carp (Cyprinus carpio) is an aquatic organism of commercial value able to survive in polluted environments; carps contain proteolytic enzymes of physiological importance and potential industrial application. The objective of this work was partially purify and study the proteolytic activity at different pH of carp proteases living in a polluted environment. Three carps were captured in different zones of Zumpango polluted lagoon (Mexico) at 1 m of maximum deep. Protease crude extracts were obtained from dorsal muscle by aqueous extraction and fractionated by 20 %, 50 %, 80 %-saturated (NH4)2SO4. Fractions extracted with 50 % and 80 %-saturated (NH4)2SO4 were selected for their high proteolytic activity and concentrated by ultrafiltration through 100 kDa molecular weight cutoff membranes and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The crude proteolytic extract had significantly higher activity (19.7 - 20.3 U / mg) at pH 2, 5, and 7 (P &lt; 0.001). Fractions obtained with 20 %, 50 % and 80 % - saturated (NH4)2SO4 showed peak activity at pH 5 (2.8 U / mg) and pH 6 (2.2 U / mg); pH 6 (4.3 U / mg) and pH 3 - 4 (3.6 - 3.7 U / mg); pH 3 (10.8 U / mg) and pH 10 (10.6 U / mg); respectively. Subfractions of &lt; 100 kDa, obtained with 50 % and 80 %-saturated (NH4)2SO4, had peak proteolytic activity at alkaline pH. A &lt; 100 kDa fraction, obtained with 80 %-saturated (NH4)2SO4, had the highest proteolytic activity (37.3 - 43.7 U / mg) at pH 8 - 10, purification factor of 3 and 19.1 % recovery. Thirteen proteins between 9.8 to 104.8 kDa were identified in the crude extract. Peak protein concentration was observed for 31 - 33 and 39 - 41 kDa, suggesting the possibility predominance of serine- and aspartyl- proteases, respectively. We suggest this protease with maximum activity at alkaline pH is related to the adaptation of C. carpio to polluted waters with high pH. Although unsuitable for human consumption, these organisms can be a source of protease production aimed to several uses as in the industry and waste water treatment among others.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[carpa común]]></kwd>
<kwd lng="es"><![CDATA[Cyprinus carpio]]></kwd>
<kwd lng="es"><![CDATA[proteasas]]></kwd>
<kwd lng="es"><![CDATA[agua contaminada]]></kwd>
<kwd lng="es"><![CDATA[laguna]]></kwd>
<kwd lng="en"><![CDATA[common carp]]></kwd>
<kwd lng="en"><![CDATA[Cyprinus carpio]]></kwd>
<kwd lng="en"><![CDATA[proteases]]></kwd>
<kwd lng="en"><![CDATA[contaminated water]]></kwd>
<kwd lng="en"><![CDATA[lagoon]]></kwd>
</kwd-group>
</article-meta>
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