Optimization of enzymatic preparation of glucose 1-phosphate by response surface methodology / 生物工程学报

With glucose as substrate, sodium tripolyphosphate as the phosphorus acylating agent, and phosphorylase of Solanum tuberosum as the catalyst, glucose 1-phosphate was synthesized. Based on a three-level, three-variable Box-Behnken experimental design, response surface methodology was used to evaluate the effects of temperature, molar ratio of glucose to sodium tripolyphosphate and time on the production. The structure of the product was confirmed by 1H NMR spectra. The results show that the optimum conditions were as follows: temperature 35 degrees C, molar ratio of glucose to sodium tripolyphosphate 1.35:1 and time 19 h.

Comparison of the recombinant glucosephosphate isomerase from different zymodemes of entamoeba histolytica with their natural counterparts by isoenzyme electrophoresis

Entamoeba histolytica is the etiological agent of invasive amoebiasis, the third leading parasitic cause of mortality in the world. Our aim was to find a molecular correlation between a glucosephosphate isomerase zymodeme analyses in E. histolytica zymodemes. It was demonstrated that natural and recombinant glucosephosphate isomerase enzymes of E. histolytica comigrated in the starch gel electrophoresis, indicating that the isoenzyme pattern of E. histolytica glucosephosphate isomerase could be explained from the primary sequences alone and means that expression of the polypeptides of the described sequences in Escherichia coli are able to reproduce the classical glucosephosphate isomerase isoenzyme patterns

Structural and cytochemical localization of the endoplasmic reticulum in the electrocyte of electrophorus electricus

Vesículas com vários diâmetros variando entre 0.06 e 0.6 micronm e localizadas em torno do núcleo, bem como na proçäo mais periférica, foram observadas no electrócito do peixe elétrico Electrophorus electricus. Tais vesículas foram consideradas como componentes de retículo endoplasmático do eletrócito uma vez que observaçöes citoquímicas demonstraram a presença de glicose-6-fosfatase na membrana dessas vesículas. Esta idéia é reforçada por resultados obtidos com o uso da técnica do pirantiminiato de potássio e análise espectroscópica de elétrons, que mostrou a presença da Ca++ na membrana das vesiculas

Glucose release by the liver under conditions of reduced activity of glucose 6-phosphatase

An inhibitor of glucose 6-phosphatase, isosteviol, was used in liver perfusion experiments to obtain a rough estimate of the control strength of the enzyme. Isosteviol only inhibited glucose release at high concentrations (1 mM), well above that needed for half-maximal action (70 micrnM). The decrease in glucose release was followed by an increase in the intracellular glucose 6-phosphate concentration. It was concluded that the control strength of glucose-6-phosphatase is relatively low

Estudio de la glucosa 6 fosfato deshidrogenasa, de la hexoquinasa y de la fosfohexaisomerasa eritrocitaria de recién nacidos / Study of erythrocyte glucose-6-phosphate-dehydrogenase, hexokinase and phosphohexosaisomerase in newborn infants

Durante el desarrollo ontogénico se observan cambios en los patrones enzimáticos diferenciales característicos en muchos tejidos, sugiriendo que la actividad metabólica varía con la edad; dichas diferencias son mas apreciables durante la etapas embrionarias y las primeras etapas post-natal. En el eritrocito se ha demostrado que los patrones enzimáticos dependen de la edad celular y que ademas presenta diferentes tipos de Hb durante la ontogénesis; lo que nos sugirió que era de interes el estudio de algunas enzimas eritrocitarias del recién nacido y su comparación con un grupo control adulto. Se estudiaron 3 enzimas eritrocitarias: la Hexoquinasa (Hx 2:7:1:1), la Fosfohexosaisomerasa (FHI 5::3:1:9) y la glucosa 6 Fosfato Deshidrogenasa (G6FD 1:1:1:49) No se encontraron diferencias significativas entre los valores medios de las 3 enzimas estudiadas entre recién nacidos masculinos y femeninos. Se encontró solamente diferencia significativa entre los valores medios de la Hx entre R.N de diferentes grupos raciales, siendo mas alto el valor, en el grupo europoide (p < 0.05. En cambio, cuando se comparó un grupo de R.N del sexo masculino y del grupo racial europoide con un grupo control de adultos con características similares, se encontraron valores significativamente más altos en los valores medios de las 3 enzimas estudiadas

Doseamento da atividade da glicose-6-fosfato desidrogenase em células in vitro / Evaluation of glucose-6-phosphate dehydrogenase activity in cells in vitro

A atividade de glicose-6-fosfato desidrogenase em células in vitro foi determinada através de método espectrofotométrico. Foi estabelecida a densidade populacional adequada e padronizaram-se as condiçöes para extraçäo da enzima e para o desenvolvimento da reaçäo

Valores de sodio e potassio em sangue conservado em citrate-phosphate-dextrose. / Sodium and potassium levels in blood preserved in citrate-phosphate-dextrose

Neste estudo foram avaliados os valores das concentracoes de sodio e potassio em sangue total em bolsas contendo volumes de Citrate-Phosphate-Dextrose (CPD). Mostramos haver correlacao das concentracoes de sodio com os diferentes volumes coletados nas bolsas e das concentracoes de potassio com o tempo de estocagem