MAXIMUM ACTIVITIES OF KEY ENZYMES OF GLYCOLYSIS, GLUTAMINOLYSIS, PENTOSE-PHOSPHATE PATHWAY AND TRICARBOXYLIC-ACID CYCLE IN NORMAL, NEOPLASTIC AND SUPPRESSED CELLS
MAXIMUM ACTIVITIES OF KEY ENZYMES OF GLYCOLYSIS, GLUTAMINOLYSIS, PENTOSE-PHOSPHATE PATHWAY AND TRICARBOXYLIC-ACID CYCLE IN NORMAL, NEOPLASTIC AND SUPPRESSED CELLS
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DOI：
10.1042/bj2650503
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发表时间：
1990-01-15
影响因子：
4.1
通讯作者：
NEWSHOLME, EA
中科院分区：
文献类型：
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作者：
BOARD, M;HUMM, S;NEWSHOLME, EA
1.糖酵解，戊糖磷酸途径，三羧酸循环和β-氨基分解的一些关键酶的最大活动进行了测量，在匀浆从各种正常的，肿瘤和抑制细胞。2.己糖激酶和6-磷酸果糖激酶的相对活性表明，特别是在肿瘤细胞中，其中葡萄糖转运的能力是高的，己糖激酶可以接近饱和，相对于细胞内的葡萄糖，因此，己糖激酶和磷酸果糖激酶可以在这些细胞中的糖酵解通量的调节中发挥重要作用。3.丙酮酸激酶的活性在致瘤细胞中比在非致瘤细胞中高得多，并且在转移细胞中比在致瘤细胞中高：对于非致瘤细胞，活性范围为28.4至574 nmol/min，对于致瘤细胞，活性范围为899至1280 nmol/min，并且对于转移细胞，活性范围为1590至1627 nmol/min/mg蛋白质。4.丙酮酸激酶活性与2 × 在肿瘤细胞中磷酸果糖激酶活性非常高。肿瘤细胞的平均值为22.4，而来自60种不同动物的肌肉的平均值仅为3.8.5。柠檬酸合酶和异柠檬酸脱氢酶的活性都存在于非肿瘤和肿瘤细胞中，这表明三羧酸循环酶的完整补体存在于这些肿瘤细胞中。6.在肿瘤细胞中，谷氨酰胺酶的活性类似于或大于己糖激酶的活性，这表明谷氨酰胺在这些细胞中的能量产生中可能与葡萄糖一样重要。
1. Maximal activities of some key enzymes of glycolysis, the pentose phosphate pathway, the tricarboxylic acid cycle and glutaminolysis were measured in homogenates from a variety of normal, neoplastic and suppressed cells. 2. The relative activities of hexokinase and 6-phosphofructokinase suggest that, particularly in neoplastic cells, in which the capacity for glucose transport is high, hexokinase could approach saturation in respect to intracellular glucose; consequently, hexokinase and phosphofructokinase could play an important role in the regulation of glycolytic flux in these cells. 3. The activity of pyruvate kinase is considerably higher in tumorigenic cells than in non-tumorigenic cells and higher in metastatic cells than in tumorigenic cells: for non-tumorigenic cells the activities range from 28.4 to 574, for tumorigenic cells from 899 to 1280, and for metastatic cells from 1590 to 1627 nmol/min per mg of protein. 4. The ratio of pyruvate kinase activity to 2 .times. phosphofructokinase activity is very high in neoplastic cells. The mean is 22.4 for neoplastic cells, whereas for muscle from 60 different animals it is only 3.8.5. Both citrate synthase and isocitrate dehydrogenase activities are present in non-neoplastic and neoplastic cells, suggesting that the full complement of tricarboxylic-acid-cycle enzymes are present in these latter cells. 6. In neoplstic cells, the activity of glutaminase is similar to or greater than that of hexokinase, which suggests that glutamine may be as important as glucose for energy generation in these cells.