RESUMEN
Estrogenic potency of six triterpene glycosides, Holothurin A, Holotoxin A1, Frondoside A, Cucumarioside A2-2 and Cauloside C, that are natural products and semi-synthesized Ginsenoside-Rh2, were examined with yeast two-hybrid system, including expressed genes of human estrogen receptor, hERalpha, the co-activator TIF2 and lacZ as a reporter gene. Only Ginsenoside-Rh2 exhibited significant moderate estrogenic activity in the concentration range of 10(-7) to 10(-6)M. Its effect was approximately 30% of the activity of 17beta-estradiol applied at half-effective concentration. This indicates Ginsenosides-Rh2 is a weak phytoestrogen. The sea cucumber triterpene glycosides, Holothurin A, Holotoxin A1, Cucumarioside A2-2 and Frondoside A, and plant glycoside Cauloside C had no appreciable estrogenic activity. Data obtained by yeast two-hybrid assay reflect structure-activity relationship between tested compounds and 17beta-estradiol. Only Ginsenoside-Rh2 has some similarity in chemical structure with 17beta-estradiol that might explain affinity of this glycoside to the hERalpha receptor.
Asunto(s)
Glicósidos/química , Receptores de Estrógenos/química , Triterpenos/química , Animales , Relación Dosis-Respuesta a Droga , Humanos , Estructura Molecular , Técnicas del Sistema de Dos HíbridosRESUMEN
An alkaline phosphatase with unusually high specific activity has been found to be produced by the marine bacterium Cobetia marina (strain KMM MC-296) isolated from coelomic liquid of the mussel Crenomytilus grayanus. The properties of enzyme, such as a very high specific activity (15000 DE U/1 mg of protein), no activation with divalent cations, resistance to high concentrations of inorganic phosphorus, as well as substrate specificity toward 5' nucleotides suggest that the enzyme falls in an intermediate position between unspecific alkaline phosphatases (EC 3.1.3.1) and 5' nucleotidases (EC 3.1.3.5).
Asunto(s)
5'-Nucleotidasa/aislamiento & purificación , Fosfatasa Alcalina/aislamiento & purificación , Halomonadaceae/enzimología , Mytilidae/microbiología , Animales , Concentración de Iones de Hidrógeno , Punto Isoeléctrico , Peso Molecular , Océano Pacífico , Especificidad por SustratoRESUMEN
We studied expression of inducible NO synthase gene in human brain under conditions of acute or chronic intoxication. Acute alcohol intoxication was accompanied by changes in enzyme expression in certain brain structures.