Sample records for TIROSINASA (tyrosinase)
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1

DOCKING DE CICLOARTANOS INHIBIDORES DE TIROSINASA/ DOCKING OF TYROSINASE CICLOARTANE INHIBITORS

GUTIÉRREZ, Pablo A; ROJANO, Benjamín A
2009-05-01

Resumen en español El berenjenol (21:24-epoxi-24-metil-cicloartano), aislado a partir las hojas de Oxandra cf. xylopioides (Annonaceae), y sus derivados hemisintéticos, berenjenol-3-acetato y 3-oxo-berenjenol son inhibidores de la enzima tirosinasa (EC 1.14.18.1). Estos compuestos son triterpenos de tipo cicloartano, y pese a que existen estudios de estructura actividad sobre compuestos similares, su mecanismo de inhibición no está bien establecido. En este trabajo se realiza un estudio (mas) de docking sobre el berenjenol y sus derivados, que sugiere un marco racional para interpretar la actividad de estos compuestos teniendo en cuenta sus interacciones con la tirosinasa. Este estudio permite concluir que el berenjenol actúa como inhibidor competitivo uniéndose al sitio activo de la tirosinasa mediante interacciones con los aminoácidos Ile42, Met43 Arg55, Trp184, Asn191, His194, Val195, Ala202, Met201 y Thr203. Resumen en inglés Berenjenol (21:24-epoxy-24-methyl-cicloartane) isolated from leaves of Oxandra cf. xylopioides (Annonaceae), and its synthetic derivatives Berenjenol-3-acetate and 3-Oxoberenjenol are tyrosinase inhibitors (EC 1.14.18.1). These compounds are triterpenoids type cycloartanes, whose structure-activity relationship has been studied on similar compounds. However, the mechanism of inhibition of these molecules is not well understood. This paper present the results of a docking (mas) study between Berenjenol and its derivatives on tyrosinase enzyme that provides a rational framework for understanding the activity of these compounds. According to this work, Berenjenol acts as a competitive inhibitor of tyrosinase through interactions with Ile42, Met43 Arg55, Trp184, Asn191, His194, Val195, Ala202, Met201 and Thr203.

Scientific Electronic Library Online (Spanish)

2

EFECTO DE LA TÉCNICA DE EXTRACCIÓN DE RUTA GRAVEOLENS SOBRE LA ACTIVIDAD ANTITIROSINASA Y CORRELACIÓN ENTRE LA INHIBICIÓN ENZIMÁTICA, EL CONTENIDO DE COMPUESTOS FENÓLICOS Y LA CITOTOXICIDAD/ EFFECT OF EXTRACTION TECHNIQUE OF RUTA GRAVEOLENS ON ANTITYROSINASE ACTIVITY AND CORRELATION AMONGST INHIBITORY ACTIVITY, PHENOLIC COMPOUNDS CONTENT AND CYTOTOXICITY

MUÑOZ D., Katalina; LONDOÑO L., Julián A.; ARANGO A., Gabriel J.; SIERRA R., Jelver A.; BRAVO M., Karent E.
2007-07-01

Resumen en español La pigmentación de la piel es el resultado de la producción y distribución de melanina, un pigmento que es formado por la oxidación sucesiva de la L-Tirosina a L-Dihidroxifenilalanina (L-DOPA) y dopaquinona por el enzima tirosinasa. Las irregularidades en la pigmentación de la piel son un problema estético para muchos individuos. Es por ello que actualmente existe un gran interés en investigar productos con propiedades aclaradoras de la piel. Con el propósito de b (mas) uscar inhibidores del enzima tirosinasa a partir de productos naturales, se estudian extractos de Ruta graveolens (R. graveolens) empleando diferentes métodos de extracción. Se determina la inhibición de la oxidación de la L-Tirosina catalizada por tirosinasa de hongo y se correlaciona esta actividad con la citotoxicidad y el contenido de compuestos fenólicos, pues se ha reportado que existe actividad inhibidora de este enzima por algunos de estos compuestos. Se encuentra que el método de extracción influye sustancialmente en el contenido de compuestos fenólicos y en la citotoxicidad, mientras ejerce un efecto modesto sobre la actividad inhibidora de tirosinasa. Resumen en inglés Skin pigmentation is the consequence of melanin production and dispersion, this pigment is formed by a successive oxidation of L-Tyrosine into L-Dihydroxyphenylalanine (L-DOPA) and dopaquinone by Tyrosinase enzyme. Skin pigmentation irregularities become an aesthetic problem for many people. Therefore there is a big interest in research on products with skin lightening properties. In order to find inhibitors of Tyrosinase enzyme from natural product, extracts of Ruta grav (mas) eolens (R. graveolens) were studied by using different extraction methods. The inhibition of the oxidation of L-Tyrosine catalyzed by mushroom tyrosinase is determined and correlated with cytotoxicity and the content of phenolic compounds, because inhibitory activity on the enzyme has been reported of these kind of compounds. It found that the extraction method affects strongly the content of phenolic compounds of the extract and the cytotoxicity as well, in contrast with the inhibition of tyrosinase activity which remains almost unaffected.

Scientific Electronic Library Online (Spanish)

3

Detección mediante RT-PCR de células tumorales circulantes en pacientes con melanoma maligno en estadio III: Correlación con el grosor y la histología del tumor

Carrillo, E.; Prados, J.; Melguizo, C.; Marchal, J. A.; Boulaiz, H.; Serrano, S.; Aránega, A.
2001-09-01

Resumen en español El objetivo de nuestro estudio ha sido evaluar la utilidad de la Transcriptasa reversa y Reacción en cadena de la polimerasa (RT-PCR) en la detección de la enzima tirosinasa como marcador de la presencia de células derivadas de melanocitos en pacientes con melanoma maligno en estadio III y su correlación con factores pronósticos como el grosor y la forma clínico-histológica del tumor. La detección de células de melanoma circulantes mediante RT-PCR se ha realizado (mas) en un grupo de 28 pacientes con melanoma maligno en estadio III (clasificación de la AJCC). Nuestros resultados demuestran una alta positividad de la PCR en este grupo de pacientes siendo más frecuente en tumores con un grosor 4mm (75%). No obstante, no encontramos correlación entre la positividad de la PCR y la forma clínico-histológica del tumor. Nuestros resultados sugieren la posibilidad de aplicar la detección del ARNm de la tirosinasa mediante RT-PCR como un nuevo marcador en el pronóstico del melanoma maligno. Resumen en inglés The objetive of our study was to evaluate the utility of the reverse transcriptase-polymerase chain reaction (RT-PCR) in the detection of the tyrosinase enzyme as a marker of circulating melanocites in melanoma patients (stage III) and the correlation with prognostic factors such as thickness and histologic type tumors. Melanoma cells were identified through the tyrosinase mRNA by RT-PCR from 28 patients with stage III of malignant melanoma (classified to the AJCC guideli (mas) nes). Our findings showed a high PCR positivity from patients in stage III, which were more frequent in primary tumors measuring 4mm (75%). However, no correlation was observed between the positive PCR results and the histological appearance of the primary tumor. Our results suggest the possible application of the PCR assay for tyrosinase mRNA as a new marker in judging the prognosis of malignant melanoma.

Scientific Electronic Library Online (Spanish)

4

Variación estacional y potencial enzimático de microhongos asociados con la descomposición de hojarasca de Nothofagus pumilio/ Seasonal variation and enzymatic potential of microfungi associated with the decomposition of Nothofagus pumilio leaf litter

VALENZUELA, EDUARDO; LEIVA, SERGIO; GODOY, ROBERTO
2001-12-01

Resumen en español Se estudió la variación estacional y el potencial enzimático de microhongos aislados desde el follaje y hojarasca de Nothofagus pumilio sometida a degradación natural durante 1 año. La investigación se realizó en un bosque de N. pumilio ubicado en una microcuenca del Valle de Antillanca, Parque Nacional Puyehue (40° 47' S, 72° 12' O, 1.120 m de altitud). Hojas senescentes colectadas desde árboles de N. pumilio se depositaron en bolsas de malla de nylon ("litter (mas) bags") y se sometieron a degradación natural en el piso del bosque durante 1 año (marzo 1997-marzo 1998), realizando muestreos trimestrales. Para el aislamiento de microhongos desde las hojas se utilizó el método de las diluciones, con agar extracto de malta al 2 % como medio de cultivo. Para determinar los potenciales degradativos de los aislamientos, se analizaron in vitro las actividades de amilasa, celulasa, pectinasa, proteasa, lacasa, oxidasa extracelular, peroxidasa, citocromo oxidasa, fosfatasa, esterasa y tirosinasa. Las principales especies aisladas en las hojas senescentes fueron Alternaria alternata, Cladosporium cladosporioides, Epicoccum nigrum, Phialophora grupo hoffmannii y Rhodotorula aurantiaca. Las especies dominantes en la hojarasca fueron Hormonema prunorum, Mortierella ramanniana var. angulispora, Penicillium para-herquei y Trichoderma polysporum. El mayor potencial enzimático lo exhibieron Moniliales y micelios estériles, mientras el menor Sphaeropsidales y levaduras. Las especies más activas fueron Alternaria alternata, Cladosporium cladosporioides, Hormonema prunorum y Phialophora malorum. Las actividades de celulasa y amilasa fueron las más importantes. De las enzimas ligninolíticas, oxidasa extracelular y peroxidasa presentaron los más elevados potenciales enzimáticos Resumen en inglés The seasonal variation and enzymatic potential of microfungi isolated from senescent leaves and leaf litter of Nothofagus pumilio was studied. The study was performed in a N. pumilio forest located in a microcatchment of the Antillanca Valley, Puyehue National Park (40º 47' S, 72° 12' W, 1,120 m of altitude). Senescent leaves recently collected from N. pumilio trees were enclosed in litter bags and subjected to natural degradation on the forest leaf litter during 1 year (mas) (March 1997-March 1998), with seasonal sampling. The isolation of microfungi was performed through the dilution plate technique using malt extract agar (2 %) as the isolation medium. The enzymatic degradation potential of microfungi was determined in vitro by testing amylase, cellulase, pectinase, protease, laccase, extracellular oxidase, peroxidase, cytochrome oxidase, phosphatase, esterase and tyrosinase activities. The mycoflora of the senescent leaves was dominated by Alternaria alternata, Cladosporium cladosporioides, Epicoccum nigrum, Phialophora group hoffmanni and Rhodotorula aurantiaca. The most abundant species found in the leaf litter were Hormonema prunorum, Mortierella ramannniana var. angulispora, Penicillium para-herquei and Trichoderma polysporum. The Moniliales and sterile micelia exhibited the highest enzymatic degradation potential, being the lowest Sphaeropsidales and yeasts. Individually, the species with the highest degradative potential were Alternaria alternata, Cladosporium cladosporioides, Hormonema prunorum and Phialophora malorum. Cellulase and amylase activities were the most important. Extracellular oxidase and peroxidase were the ligninolitic enzymes with the highest enzymatic potentials

Scientific Electronic Library Online (Spanish)

6

Tyrosinase gene expression is not detected in mouse brain outside the retinal pigment epithelium cells

Giménez, Estela; Lavado, Alfonso J.; Giraldo, Patricia; Montoliu, Lluís

4 pages, 3 figures.-- PMID: 14622170 [PubMed]. | Tyrosinase is the rate-limiting enzyme for melanin synthesis. Its gene is expressed in two cell types: melanocytes, derived from migrating neural crest cells, and, in the CNS, retinal pigment epithelium cells, derived from the optic cup. Its absence f...

DRIVER (Spanish)

7

Tyrosinase gene expression is not detected in mouse brain outside the retinal pigment epithelium cells

Giménez, Estela; Lavado, Alfonso J.; Giraldo, Patricia; Montoliu, Lluís
2003-10-27

Digital.CSIC (Spain)

8

The oxidation of l-ascorbic acid catalysed by pear tyrosinase

Espín de Gea, Juan Carlos; Wichers, Harry J.; Veltman, Rob H.
2000-01-01

Digital.CSIC (Spain)

9

Synthesis of the Antioxidant Hydroxytyrosol Using Tyrosinase as Biocatalyst

Espín de Gea, Juan Carlos; Soler-Rivas, Cristina; Cantos Villar, Emma; Tomás Barberán, Francisco; Wichers, Harry J.
2001-02-10

Digital.CSIC (Spain)

10

Regional abnormalities in retinal development are associated with local ocular hypopigmentation

Giménez, Estela; Lavado, Alfonso J.; Jeffery, Glen; Montoliu, Lluís
2005-03-31

Digital.CSIC (Spain)

11

On the use of regulatory regions from pigmentary genes to drive the expression of transgenes in mice

Montoliu, Lluís; Larue, Lionel; Beermann, Friedrich

Letter to the Editor.-- 3 pages, 1 figure.-- PMID: 15016310 [PubMed]. | The combination of known regulatory regions from mammalian genes and the coding regions of exogenous genes has been instrumental for the generation and analysis of transgenic mice and influences the resulting expression pattern ...

DRIVER (Spanish)

13

New animal models to study the role of tyrosinase in normal retinal development

Lavado, Alfonso J.; Montoliu, Lluís

10 pages.-- PMID: 16146766 [PubMed]. | Albino animals display a hypopigmented phenotype associated with several visual abnormalities, including rod photoreceptor cell deficits, abnormal patterns of connections between the eye and the brain and a general underdevelopment of central retina. Oculocutan...

DRIVER (Spanish)

15

Molecular basis of the extreme dilution mottled mouse mutation: A combination of coding and non-coding genomic alterations

Lavado, Alfonso J.; Olivares, Concepción; García-Borrón, José Carlos; Montoliu, Lluís
2004-11-30

Digital.CSIC (Spain)

16

Melanin precursors prevent premature age-related and noise-induced hearing loss in albino mice

Murillo Cuesta, Silvia; Contreras, Julio; Zurita, Esther; Cediel Algovia, Rafael; Cantero, Marta; Varela-Nieto, Isabel; Montoliu, Lluís
2010-02-01

Digital.CSIC (Spain)

18

Kinetic characterization of the substrate specificity and mechanism of mushroom tyrosinase

Espín de Gea, Juan Carlos; Varón, Ramón; Fenoll, Lorena G.; Gilabert, M. Ángeles; García-Ruíz, Pedro; Tudela, José; García-Cánovas, Francisco
2000-02-01

Digital.CSIC (Spain)

19

Identification and functional validation of a 5' upstream regulatory sequence in the human tyrosinase gene homologous to the locus control region of the mouse tyrosinase gene

Regales, Lucía; Giraldo, Patricia; García-Díaz, Ángel; Lavado, Alfonso J.; Montoliu, Lluís

8 pages, 4 figures.-- PMID: 14629727 [PubMed]. | Comparison analysis of the sequences of the mouse and human genomes has proven a powerful approach in identifying functional regulatory elements within the non-coding regions that are conserved through evolution between homologous mammalian loci. Here...

DRIVER (Spanish)

21

Functional dissection of the mouse tyrosinase locus control region identifies a new putative boundary activity

Giraldo, Patricia; Martínez, Antonio; Regales, Lucía; Lavado, Alfonso J.; García-Díaz, Ángel; Alonso, Ángel

16 pages, 6 figures.-- PMID: 14576318 [PubMed].-- PMCID: PMC275449.-- DDBJ/EMBL/GenBank accession nos X76647, AF364302.-- Supplementary Material available. | Locus control regions (LCRs) are complex high-order chromatin structures harbouring several regulatory elements, including enhancers and bound...

DRIVER (Spanish)

22

Functional dissection of the mouse tyrosinase locus control region identifies a new putative boundary activity

Giraldo, Patricia; Martínez, Antonio; Regales, Lucía; Lavado, Alfonso J.; García Cabezas, Miguel Ángel; Alonso, Ángel; Busturia, Ana; Montoliu, Lluís
2003-11-01

Digital.CSIC (Spain)

23

Enzymatic synthesis of antioxidant hydroxytyrosol.

Espín de Gea, Juan Carlos; Tomás Barberán, Francisco; García, M. C.; Ferreres, Federico; Soler-Rivas, Cristina; Wichers, Harry J.
2002-02-28

Digital.CSIC (Spain)

24

Efficient Generation of Transgenic Mice with Intact Yeast Artificial Chromosomes by Intracytoplasmic Sperm Injection

Moreira, Pedro N.; Giraldo, Patricia; Cozar, Patricia; Pozueta, Julio; Jiménez, Adela; Montoliu, Lluís

5 pages, 1 figure.-- PMID: 15286029 [PubMed].-- Printed version published on Dec 2004.-- Open access version available at the publisher's site. | The production of animals with large transgenes is an increasingly valuable tool in biotechnology and for genetic studies, including the characterization ...

DRIVER (Spanish)

25

Efficient Generation of Transgenic Mice with Intact Yeast Artificial Chromosomes by Intracytoplasmic Sperm Injection

Moreira, Pedro N.; Giraldo, Patricia; Cozar, Patricia; Pozueta, Julio; Jiménez, Adela; Montoliu, Lluís; Gutiérrez-Adán, Alfonso
2004-07-30

Digital.CSIC (Spain)

26

Effect of captopril on mushroom tyrosinase activity in vitro

Espín de Gea, Juan Carlos; Wichers, Harry J.
2001-01-12

Digital.CSIC (Spain)

27

Ectopic expression of tyrosine hydroxylase in the pigmented epithelium rescues the retinal abnormalities and visual function common in albinos in the absence of melanin

Lavado, Alfonso J.; Jeffery, Glen; Tovar, Victoria; Villa, Pedro de la; Montoliu, Lluís

11 pages, 5 figures.-- PMID: 16445854 [PubMed].-- Printed version published on Feb 2006.-- Additional material: CSIC Press release (Spanish). | Albino mammals have profound retinal abnormalities, including photoreceptor deficits and misrouted hemispheric pathways into the brain, demonstrating that m...

DRIVER (Spanish)

30

A transgenic mouse model with inducible Tyrosinase gene expression using the tetracycline (Tet-on) system allows regulated rescue of abnormal chiasmatic projections found in albinism

Giménez, Estela; Lavado, Alfonso J.; Giraldo, Patricia; Cozar, Patricia; Jeffery, Glen; Montoliu, Lluís

8 pages, 4 figures.-- PMID: 15250938 [PubMed].-- Printed version published on Aug 2004.-- Erratum in: Pigment Cell Res. 18(3): 224 (2005) | Congenital defects in retinal pigmentation, as in oculocutaneous albinism Type I (OCA1), where tyrosinase is defective, result in visual abnormalities affecting...

DRIVER (Spanish)

32

A strategy to study tyrosinase transgenes in mouse melanocytes

Lavado, Alfonso J.; Matheu, Ander; Serrano, Manuel; Montoliu, Lluís

This article is available from: http://www.biomedcentral.com/1471-2121/6/18 | [Background] A number of transgenic mice carrying different deletions in the Locus Control Region (LCR) of the mouse tyrosinase (Tyr) gene have been developed and analysed in our laboratory. We require melanocytes from the...

DRIVER (Spanish)

33

A strategy to study tyrosinase transgenes in mouse melanocytes

Lavado, Alfonso J.; Matheu, Ander; Serrano, Manuel; Montoliu, Lluís
2005-04-12

Digital.CSIC (Spain)