Malaisse W J, Zhang T M, Verbruggen I, Willem R
Laboratory of Experimental Medicine, Brussels Free University (ULB), Belgium.
Biochem J. 1996 Aug 1;317 ( Pt 3)(Pt 3):861-3. doi: 10.1042/bj3170861.
The generation of 13C-labelled lactate by colon carcinoma cells of the Caco-2 line incubated for 120 min in the presence of [2-13C]propionate (10 mM) was assessed by 13C NMR. About 10% of the total amount of 13C-labelled lactate was recovered in the cell pellet and displayed a [2-13C]lactate/[3-13C]lactate isotopomer ratio of 1.18 +/- 0.01. An even higher isotopomer ratio of 1.53 +/- 0.14 was observed in the case of 13C-labelled lactate released by the cells into the incubation medium. These findings indicate that, in the Caco-2 cells, metabolic intermediates of the Krebs cycle undergo enzyme-to-enzyme channelling in the sequence of reactions catalysed by succinyl-CoA synthetase, succinate dehydrogenase and fumarase.
通过¹³C核磁共振评估了在含有[2-¹³C]丙酸盐（10 mM）的条件下培养120分钟的Caco-2结肠癌细胞系产生¹³C标记乳酸的情况。在细胞沉淀中回收了约10%的¹³C标记乳酸总量，其[2-¹³C]乳酸/[3-¹³C]乳酸异构体比率为1.18±0.01。在细胞释放到培养液中的¹³C标记乳酸的情况下，观察到更高的异构体比率，为1.53±0.14。这些发现表明，在Caco-2细胞中，三羧酸循环的代谢中间体在由琥珀酰辅酶A合成酶、琥珀酸脱氢酶和延胡索酸酶催化的反应序列中经历酶对酶的通道化作用。
