Hibasami H, Sakurai M, Maekawa S, Nakashima K
Department of Biochemistry, Mie University School of Medicine, Japan.
Anticancer Res. 1987 Nov-Dec;7(6):1213-6.
The catalytic activity of spermidine synthase isolated from rat ventral prostate was significantly inhibited by methylthiopropylamine (MTPA). Spermine synthase was almost insensitive to this inhibitor. Inhibition of spermidine synthase by MTPA was competitive with respect to a substrate putrescine (Ki, 3.3 = 10(-7) M), but not competitive with another substrate decarboxylated S-adenosylmethionine (dec AdoMet). MTPA inhibited the growth of human lymphoid leukemia Molt 4B cells. The spermidine content in the inhibitor-treated cells was dose-dependently depressed, whereas the putrescine content was increased concomitantly. In these spermidine depleted and growth retarded Molt 4B cells, the synthesis of protein, but not of DNA or RNA, was found to be significantly diminished.
从大鼠腹侧前列腺分离出的亚精胺合酶的催化活性受到甲基硫丙胺（MTPA）的显著抑制。精胺合酶对这种抑制剂几乎不敏感。MTPA对亚精胺合酶的抑制作用相对于底物腐胺是竞争性的（Ki，3.3 = 10(-7) M），但相对于另一种底物脱羧S-腺苷甲硫氨酸（脱羧AdoMet）则不是竞争性的。MTPA抑制人淋巴白血病Molt 4B细胞的生长。经抑制剂处理的细胞中亚精胺含量呈剂量依赖性降低，而腐胺含量则随之增加。在这些亚精胺耗竭且生长受阻的Molt 4B细胞中，发现蛋白质的合成显著减少，而DNA或RNA的合成未受影响。
