Oxidation of glucose, ribose, alanine, and glutamate by Leishmania braziliensis panamensis.
Oxidation of glucose, ribose, alanine, and glutamate by Leishmania braziliensis panamensis.
复制标题
巴西利什曼原虫巴拿马对葡萄糖、核糖、丙氨酸和谷氨酸的氧化。
DOI：
10.1111/j.1550-7408.1987.tb03156.x
复制
发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Blum,JJ
中科院分区：
文献类型：
--
作者：
Keegan,FP;Sansone,L;Blum,JJ
研究了巴西利什曼原虫（leishmania braziliensis panamensis）原毛菌对[1‐14C]‐和[6‐14C]葡萄糖、[1‐14]核糖、[1‐14C]‐和[U‐14C]丙氨酸、[1‐14C]‐和[5‐14C]谷氨酸的代谢。[1‐14C]葡萄糖产生的14co2与[6‐14C]葡萄糖产生的14co2之比约为2 - 6，表明通过戊糖磷酸途径有可观的碳流。虽然核糖的氧化速率远低于葡萄糖的氧化速率，但通过[1‐14C]核糖产生14co2进一步证明了戊糖磷酸途径的功能。[1‐14C]葡萄糖产生14co2的速率几乎与孵育时间呈线性关系，而[6‐14C]葡萄糖的速率则加快，这与孵育期间通过Embden‐Meyerhof途径增加通量的速率一致。将实验温度从26°C提高到34°C对[1‐14C]或[6‐14C]葡萄糖或[1‐14C]核糖的氧化速率或时间进程没有明显影响。丙氨酸和谷氨酸均被l氧化。B. panamensis，其氧化速率与葡萄糖的氧化速率相当或明显大于葡萄糖的氧化速率。[1‐14C]‐与[U‐14C]丙氨酸和[1‐14C]‐与[5‐14C]谷氨酸产生的14co2比率表明，这些化合物通过一个功能性的三羧酸循环代谢，并且大多数进入三羧酸循环的标签被氧化成二氧化碳。将培养物在34°C下加热6或12小时，将promastigotes转化为椭圆形的中间形式，降低葡萄糖，丙氨酸和谷氨酸的氧化速率。经过6 - h和12 - h热处理后，谷氨酸的氧化率分别降低了50%和70%。将加热后的培养物恢复到26°C，使其恢复到promastigote形式，葡萄糖氧化速率恢复，但谷氨酸氧化在26°C下19 h后仍未恢复到对照水平。
The metabolism of [1‐14C]‐ and [6‐14C]glucose, [1‐14]ribose, [1‐14C]‐ and [U‐14C]alanine, and [1‐14C]‐ and [5‐14C]glutamate by the promastigotes ofLeishmania braziliensis panamensiswas investigated in cells resuspended in Hanks' balanced salt solution supplemented with ribose, alanine, or glutamate. The ratio of14CO2produced from [1‐14C]glucose to that from [6‐14C]glucose ranged from about two to six, indicating appreciable carbon flow through the pentose phosphate pathway. A functional pentose phosphate pathway was further demonstrated by the production of14CO2from [1‐14C]ribose although the rate of ribose oxidation was much lower than the rate of glucose oxidation. The rate of14CO2production from [1‐14C]glucose was almost linear with time of incubation, whereas that of [6‐14C]glucose accelerated, consistent with an increasing rate of flux through the Embden‐Meyerhof pathway during incubation. Increasing the assay temperature from 26°C to 34°C had no appreciable effect on the rates or time courses of oxidation of either [1‐14C]‐ or [6‐14C]glucose or of [1‐14C]ribose. Both alanine and glutamate were oxidized byL. b. panamensis, and at rates comparable to or appreciably greater than the rate of oxidation of glucose. The ratios of14CO2produced from [1‐14C]‐ to [U‐14C]alanine and from [1‐14C]‐ to [5‐14C]glutamate indicated that these compounds were metabolized via a functioning tricarboxylic acid cycle and that most of the label that entered the tricarboxylic acid cycle was oxidized to carbon dioxide. Heating the cultures for 6 or 12 h at 34°C, which converts the promastigotes into an ellipsoidally shaped intermediate form, decreased the rates of oxidation of glucose, alanine, and glutamate. The oxidation of glutamate decreased by about 50% and 70% after a 6‐h or 12‐h heat treatment, respectively. Returning the heated cultures to 26°C initiated a reversion to the promastigote form and recovery of the rate of glucose oxidation, but glutamate oxidation did not return to control levels by 19 h at 26°C.