Caracterización fisicoquímica de mieles monoflorales de Euphorbia resinifera

The physicochemical characteristics of Euphorbia resinifera honey were studied. Considering the low water content, the majority of the honeys presented a proper maturity. The values of acidity revealed the absence of inappropriate fermentation, while the low values of hydroxymethylfurfural (0.4–16.48 mg/kg) were suitable for of unprocessed honeys. The average values for electrical conductivity and ashes were 451 µS/cm and 1.6 g/kg, respectively. As for the mineral content, the K was the most abundant element; Ca, Na, Mg, P, S, and Si are all present in differing quantities in the honeys. On the other hand, Principal Components Analysis (PCA) and Stepwise Discriminant Analysis (SDA) were applied to distinguish between three related Euphorbia honey types. PCA showed that the cumulative variance of the two first factors explained approximately 53%. The results of SDA showed that variables with a higher discriminant power were K, C*ab and a*, and 100% of the samples were properly classified in their corresponding class.Los parámetros fisicoquímicos de 29 de mieles monoflorales de Euphorbia resinifera fueron estudiadas. 24 parámetros, incluyendo humedad, pH, acidez (libre, lactónica y total), HMF, cenizas, conductividad eléctrica, monosacáridos (glucosa y fructosa), contenido mineral y parámetros cromáticos fueron analizados. Desde el punto de vista de su calidad las mieles fueron acordes con la legislación Europea en cuanto a contenido en agua, acidez y HMF. Los valores de cenizas y conductividad eléctrica fueron 1,6 g/kg y 451 μS/cm, respectivamente. El contenido en minerales mostró que el K es el elemento más abundante; mientras que Ca, Na, Mg, P, S y Si se presentaron en contenidos intermedios. En cuanto a los valores de los parámetros del color fueron típicos de mieles ámbar claras. Se ha realizado un análisis estadístico multivariante a los datos obtenidos para diferenciar tres especies de mieles de Euphorbia. El análisis discriminante permite diferencia las mieles por su origen botánico siendo el contenido en K, C*ab y la variable cromática a* las variables con mayor poder discriminate, siendo el 100% de las muestras clasificadas correctamente en su grupo

Young camel ceruloplasmin : purification and partial characterization

La céruloplasmine d'un chamelon âgé de six mois a été isolée et purifiée en une seule étape, utilisant une chromatographie sur Sépharose activée par de la chloroéthylamine. La masse moléculaire de la protéine a été déterminée par électrophorèse avec SDS et a été estimée à 130 000 Da. La protéine possède une mobilité électrophorétique légèrement supérieure à celle de l'homme, ce qui suggère que la céruloplasmine du chamelon est compacte et plus acide. Le nombre d'atomes de cuivre par molécule de céruloplasmine a été de 5,8 ± 0,3. Le spectre optique de la céruloplasmine du chamelon a montré une absorption maximale à 610 nm attribuée au cuivre de type 1 . Le spectre EPR a été totalement dépourvu d'un signal correspondant au cuivre de type 2. Les paramètres cinétiques de l'activité oxidasique, utilisant la p-phénylendiamine comme substrat, ont été déterminés : Km = 0,42 µM NADH/mn/mg céruloplasmine et Vmax = 0,93. Le pH optimal de l'activité a été de 5,7

Characterization of an interesting selenium-dependent glutathione peroxidase (Se-GPx) protecting cells against environmental stress: The Camelus dromedarius erythrocytes Se-GPx

Camel lives most of its life under high environmental stress in the desert. Glutathione peroxidase plays a key role in protecting cells against oxidative stress. For the first time, selenium-dependent glutathione peroxidase (Se-GPx) was purified from camel erythrocytes, biochemically characterized, and some of its properties were studied. The enzyme was purified using ethanol-chloroform treatment, acetone precipitation and ion exchange chromatography. A purification fold of 33.72 with 0.19% yield were obtained. The native molecular weight of the enzyme was estimated to be about 69 kDa. On SDS-PAGE, the enzyme was composed of two different subunits with a molecular weight of approximately 53 and 21 kDa. An optimum temperature of 47 °C and an optimum pH of 7.2 were found. The activation energy was 41.71 kJ/mol. This enzyme was inhibited by thiol reagents, D,L-Dithiothreitol and ?-Mercaptoethanol, and was sensitive to bivalent cations. The enzyme had a general specificity toward hydroperoxides, and high specificity for reduced glutathione. The purified enzyme contained 3.06 mol of selenium per mol of protein. The Km and Vmax values for hydrogen peroxide and reduced glutathione were 0.72 and 1.58 mM, and 25.33 and 31.03 U/mg, respectively. The biochemical properties of camel Se-GPx were different comparing to those of mammalian species. Lower molecular weight, heterodimeric structure, higher optimum temperature, relatively lower optimum pH, lower content of selenium and higher affinity for hydrogen peroxide at low reduced glutathione concentration, these could be explained by the fact that camel is able to live in the intense environmental stress in the desert. © 2019 Elsevier Lt

Partial Purification and Some Interesting Properties of Glutathione Peroxidase from Liver of Camel (Camelus dromedarius)

Climate change and increasing temperatures are global concerns. Well adapted to desert life, the camel (Camelus dromedarius) lives most of its life under high environmental stress and represents an ideal model for studying desert adaptation among mammals. Glutathione peroxidase is the principal antioxidant defense system capable of protecting cells from oxidative stress. Glutathione Peroxidase from camel liver was purified (11.64-fold purification with 1.73% yield) and characterized The molecular weight of the enzyme was estimated to be about 69 kDa by gel filtration and 34 kDa by SDS-PAGE, implying dimeric structure of the protein. An optimum temperature of 47°C and an optimum pH of 7.8 were found. This enzyme is a typical SH-enzyme that is inhibited by D,L-dithiothreitol and ?-mercaptoethanol and sensitive to bivalent cations. The enzyme had common specificity toward hydroperoxides and high specificity for reduced glutathione. The Km and Vmax values for hydrogen peroxide and reduced glutathione were 0.57 and 2.10 mM and 1.11 and 0.87 U/mg, respectively. The purified enzyme contained 16 ng of selenium per mg of protein. Our results show that the camel glutathione peroxidse exhibits properties different of those reported for other mammalian species. Lower molecular weight, homodimeric structure, higher optimum temperature, relatively low optimum pH, high affinity for hydrogen peroxide at low concentration of reduced glutathione and very low content of selenium could be explained by adaptation of the camel to living in the desert under intense environmental stress. © 2018, Pleiades Publishing, Ltd