Sharma V, Visen P K, Katiyar J C, Wittich R M, Walter R D, Ghatak S, Shukla O P
Int J Parasitol. 1989 Apr;19(2):191-8. doi: 10.1016/0020-7519(89)90007-6.
Spermidine was detected as the major polyamine of Ancylostoma ceylanicum as well as Nippostrongylus brasiliensis. Spermine was present in lower amounts whereas the level of putrescine was even less. S-Adenosylmethionine decarboxylase, a rate-limiting enzyme in the biosynthetic pathway of polyamines, was demonstrated at low levels in both parasites. Decarboxylation of lysine and arginine was absent or negligible and that of ornithine questionable, as the enzyme activity was not inhibited by alpha-difluoromethylornithine while RMI 71,645, an irreversible inhibitor of ornithine aminotransferase, strongly inhibited the liberation of CO2 from ornithine. High activity of ornithine aminotransferase was observed in both the parasites and may interfere with the assay for ornithine decarboxylase. Adults of A. ceylanicum were found to rapidly take up spermidine and spermine from incubation medium while uptake of putrescine was very low. These results indicate that hookworms depend on uptake and interconversion rather than de novo synthesis for their polyamine requirement.
已检测到亚精胺是锡兰钩虫和巴西日圆线虫的主要多胺。精胺含量较低，而腐胺水平更低。多胺生物合成途径中的限速酶S-腺苷甲硫氨酸脱羧酶在两种寄生虫中的水平都很低。赖氨酸和精氨酸的脱羧作用不存在或可忽略不计，鸟氨酸的脱羧作用存疑，因为该酶活性不受α-二氟甲基鸟氨酸抑制，而鸟氨酸氨基转移酶的不可逆抑制剂RMI 71,645强烈抑制鸟氨酸释放二氧化碳。在两种寄生虫中均观察到高活性的鸟氨酸氨基转移酶，这可能会干扰鸟氨酸脱羧酶的测定。发现锡兰钩虫成虫能迅速从培养液中摄取亚精胺和精胺，而腐胺的摄取量非常低。这些结果表明，钩虫对多胺的需求依赖于摄取和相互转化，而非从头合成。
