Mamont P S, Danzin C, Wagner J, Siat M, Joder-Ohlenbusch A M, Claverie N
Eur J Biochem. 1982 Apr;123(3):499-504. doi: 10.1111/j.1432-1033.1982.tb06559.x.
Biological transmethylation reactions and polyamine biosynthesis share the substrate S-adenosyl-L-methionine. Under normal conditions, decarboxylated S-adenosyl-L-methionine, the aminopropyl donor for polyamine biosynthesis, does not accumulate because of its rapid utilization in spermidine and spermine synthesis. Alteration of polyamine synthesis by DL-alpha-difluoromethylornithine, an enzyme-activated irreversible inhibitor of L-ornithine decarboxylase, leads to a striking accumulation of decarboxylated S-adenosyl-L-methionine in rat hepatoma cells cultured in vitro and in rat ventral prostate. This increase is due both to lack of putrescine and spermidine for the aminopropyltransferase reactions and to the elevation of S-adenosyl-L-methionine decarboxylase activity. The biological implications of accumulation of decarboxylated S-adenosyl-L-methionine are discussed with regard to the regulation of S-adenosyl-L-methionine decarboxylase activity and to the antiproliferative effects of DL-alpha-difluoromethylornithine.
生物甲基化反应和多胺生物合成共用底物S-腺苷-L-甲硫氨酸。在正常情况下，作为多胺生物合成的氨丙基供体的脱羧S-腺苷-L-甲硫氨酸不会积累，因为它在亚精胺和精胺合成中被迅速利用。L-鸟氨酸脱羧酶的酶激活不可逆抑制剂DL-α-二氟甲基鸟氨酸改变多胺合成，导致在体外培养的大鼠肝癌细胞和大鼠腹侧前列腺中脱羧S-腺苷-L-甲硫氨酸显著积累。这种增加既是由于氨丙基转移酶反应缺乏腐胺和亚精胺，也是由于S-腺苷-L-甲硫氨酸脱羧酶活性的升高。关于S-腺苷-L-甲硫氨酸脱羧酶活性的调节以及DL-α-二氟甲基鸟氨酸的抗增殖作用，讨论了脱羧S-腺苷-L-甲硫氨酸积累的生物学意义。
