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首页> 外文期刊>Infection and immunity >Enzymatic activities of cell-free extracts of Rickettsia typhi.
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Enzymatic activities of cell-free extracts of Rickettsia typhi.

机译：伤寒立克次体无细胞提取物的酶活性。

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Cell-free extracts of Rickettsia typhi were tested for activities of enzymes of the tricarboxylic acid cycle, of glutamate catabolism, and of glycolysis. The organisms were grown in the yolk sacs of chicken embryos, harvested shortly before the time of embryo death, purified by Renografin density gradient centrifugation, and ruptured in a French pressure cell. The following enzymatic activities were demonstrated: high levels of malate dehydrogenase (MDH), moderate levels of glutamate-oxaloacetate transaminase, glutamate, succinate, and isocitrate dehydrogenases, and citrate synthase, and low levels of glutamate-pyruvate transaminase. The specific activities of some of these enzymes were higher when the rickettsiae were harvested at a time of active proliferation, 3 to 4 days prior to embryo death. Rickettsial MDH was differentiated from host MDH by its migration pattern on polyacrylamide gel electrophoresis. The activities of MDH and two other dehydrogenases, demonstrable after the cells had been disrupted, were absent from purified, intact rickettsial preparations. No activity was detected for glucose-6-phosphate, 6-phosphogluconate, glyceraldehyde-3-phosphate, lactate dehydrogenases, phosphoglucose isomerase, fructoaldolase, or pyruvate kinase. Our results suggest that extracts of R. typhi that contain demonstrable enzymes involved in the catabolism of glutamate and tricarboxylic acid cycle intermediates, unlike Coxiella burnetti, lack detectable glycolytic activity.
机译：测试了伤寒立克次体的无细胞提取物的三羧酸循环酶，谷氨酸分解代谢和糖酵解活性。该微生物在鸡胚的卵黄囊中生长，在胚胎死亡前不久收获，通过肾上腺素浓度梯度离心法纯化，并在法国压力细胞中破裂。证明了以下酶活性：高水平的苹果酸脱氢酶（MDH），中等水平的谷氨酸-草酰乙酸转氨酶，谷氨酸，琥珀酸和异柠檬酸脱氢酶，柠檬酸合酶，以及低水平的谷氨酸-丙酮酸转氨酶。在胚胎死亡前3至4天的活跃增殖时期收获立克次体时，其中某些酶的比活更高。立克次体MDH通过其在聚丙烯酰胺凝胶电泳上的迁移模式而与宿主MDH区分开。纯化，完整的立克次氏菌制剂不存在MDH和其他两种脱氢酶的活性，这些活性可在细胞破裂后证实。未检测到6-磷酸葡萄糖，6-磷酸葡萄糖酸酯，-3-磷酸甘油醛，乳酸脱氢酶，磷酸葡萄糖异构酶，果糖醛缩酶或丙酮酸激酶的活性。我们的研究结果表明，伤寒沙门氏菌的提取物含有可证明的参与谷氨酸和三羧酸循环中间体分解代谢的酶，与柯氏杆菌燃烧不一样，它缺乏可检测的糖酵解活性。

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