Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
Más filtros












Base de datos
Intervalo de año de publicación
1.
Food Chem ; 257: 302-309, 2018 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-29622215

RESUMEN

The unplanned inclusion of antinutrients in fish food affects many biological processes, such as digestibility of amino acids and diet conversion, resulting in undesirable effects on body growth. Thus, the objective of this research was to propose the use of immobilized fish proteases in the detection of protease inhibitors, one of the most important antinutrients. In order to evaluate the detection of antinutritional factors through the immobilized trypsin, the enzyme was incubated with eight diets developed for commercial fish, and residual activity was measured. Comparatively, the tilapia trypsin showed an inhibition of antinutrients (protease inhibitors), present in the eight studied diets, up to 48% greater than the porcine trypsin immobilized in magnetic chitosan. Thus, it is possible to suggest the use of immobilized derivatives containing specific proteases of the target organism in the detection of antinutritional factors that reduce animal's digestive capacity and negatively influence their growth during husbandry.


Asunto(s)
Alimentación Animal/análisis , Quitosano/química , Tripsina/química , Animales , Acuicultura/métodos , Digestión , Enzimas Inmovilizadas/química , Proteínas de Peces/química , Magnetismo , Tilapia
2.
Food Chem ; 129(3): 777-82, 2011 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-25212298

RESUMEN

An alkaline peptidase was purified from the viscera of the silver mojarra (Diapterus rhombeus) in a three-step process: heat treatment, ammonium sulphate fractionation and molecular exclusion chromatography (Sephadex® G-75), with final specific activity 86-fold higher than the enzyme extract and yield of 22.1%. The purified enzyme had an estimated molecular mass of 26.5kDa and NH2-terminal amino acid sequence IVGGYECTMHSEAHE. Higher enzyme activity was observed at pH 8.5 and between 50 and 55°C. The enzyme was completely inactivated after 30min at 55°C and it was significantly more stable at alkaline pH. Km, Kcat and Kcat·Km(-1) values, using BApNA as substrate, were 0.266mM, 0.93s(-1) and 3.48mM(-1)s(-1), respectively. Enzyme activity increased in the presence of the ions (1mM) K(+), Li(+) and Ca(2+), but was inhibited by Fe(2+), Cd(2+), Cu(2+), Al(3+), Hg(2+), Zn(2+) and Pb(2+) as well as by the trypsin inhibitors TLCK and benzamidine.

3.
Biochem Biophys Res Commun ; 396(3): 667-73, 2010 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-20438707

RESUMEN

An enzyme was purified from the pyloric caecum of tambaqui (Colossoma macropomum) through heat treatment, ammonium sulfate fractionation, Sephadex G-75 and p-aminobenzamidine-agarose affinity chromatography. The enzyme had a molecular mass of 23.9 kDa, NH(2)-terminal amino acid sequence of IVGGYECKAHSQPHVSLNI and substrate specificity for arginine at P1, efficiently hydrolizing substrates with leucine and lysine at P2 and serine and arginine at P1'. Using the substrate z-FR-MCA, the enzyme exhibited greatest activity at pH 9.0 and 50 degrees C, whereas, with BAPNA activity was higher in a pH range of 7.5-11.5 and at 70 degrees C. Moreover, the enzyme maintained ca. 60% of its activity after incubated for 3h at 60 degrees C. The enzymatic activity significantly decreased in the presence of TLCK, benzamidine (trypsin inhibitors) and PMSF (serine protease inhibitor). This source of trypsin may be an attractive alternative for the detergent and food industry.


Asunto(s)
Peces/metabolismo , Tripsina/química , Secuencia de Aminoácidos , Animales , Hidrólisis , Datos de Secuencia Molecular , Inhibidores de Proteasas/farmacología , Especificidad por Sustrato , Compuestos de Tosilo/farmacología , Clorometilcetona Tosilisina/farmacología , Tripsina/aislamiento & purificación , Inhibidores de Tripsina/farmacología
4.
J Agric Food Chem ; 58(10): 6433-9, 2010 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-20426469

RESUMEN

A trypsin from the viscera of the lane snapper (Lutjanus synagris) was purified by heat treatment, fractionation with ammonium sulfate and affinity chromatography. The molecular weight of the enzyme was estimated to be 28.4 kDa (SDS-PAGE). The purified enzyme was capable of hydrolyzing the specific substrate for trypsin benzoyl-arginine-p-nitroanilide (BApNA) and was inhibited by benzamidine and tosyl lysine chloromethyl ketone (TLCK), synthetic trypsin inhibitors and phenylmethylsulfonyl fluoride (PMSF), which is a serine-protease inhibitor. The enzyme exhibited maximal activity at pH 9.0 and 45 degrees C and retained 100% of the activity after incubation at the optimal temperature for 30 min. At a concentration of 10 mM, activity was slightly activated by Ca(2+) and inhibited by the following ions in decreasing order: Cd(2+) > Hg(2+) > Cu(2+) > Zn(2+) > Al(3+). The effects of Ba(2+), K(1+) and Li(1+) proved to be less intensive. Using 1% (w/v) azocasein as substrate, the enzyme revealed high resistance (60% residual activity) when incubated with 10% H(2)O(2) for 75 min. The enzyme retained more than 80% activity after 60 min in the presence of different surfactants (Tween 20, Tween 80 and sodium choleate). The alkaline protease demonstrated compatibility with commercial detergents (7 mg/mL), such as Bem-te-vi, Surf and Ala, retaining more than 50% of initial activity after 60 min at 25 degrees C and 30 min at 40 degrees C. The thermostability and compatibility of this enzyme with commercial detergents suggest a good potentiality for application in the detergent industry.


Asunto(s)
Detergentes/farmacología , Oxidantes/farmacología , Perciformes , Tensoactivos/farmacología , Tripsina/aislamiento & purificación , Tripsina/metabolismo , Animales , Cationes/farmacología , Cromatografía de Afinidad , Detergentes/química , Activación Enzimática/efectos de los fármacos , Estabilidad de Enzimas , Precipitación Fraccionada , Calor , Peróxido de Hidrógeno/farmacología , Residuos Industriales/análisis , Intestinos/enzimología , Especificidad por Sustrato , Inhibidores de Tripsina/farmacología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...