IDENTIFICATION AND BIOSYNTHESIS OF N-1,N-9-BIS(GLUTATHIONYL)AMINOPROPYLCADAVERINE (HOMOTRYPANOTHIONE) IN TRYPANOSOMA-CRUZI
IDENTIFICATION AND BIOSYNTHESIS OF N-1,N-9-BIS(GLUTATHIONYL)AMINOPROPYLCADAVERINE (HOMOTRYPANOTHIONE) IN TRYPANOSOMA-CRUZI
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DOI：
10.1111/j.1432-1033.1994.t01-1-01019.x
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发表时间：
1994-12-15
期刊：
影响因子：
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通讯作者：
FAIRLAMB, AH
中科院分区：
文献类型：
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作者：
HUNTER, KJ;LEQUESNE, SA;FAIRLAMB, AH
使用氚化鸟氨酸、精氨酸和赖氨酸的放射性标记研究以及相关的氨基酸脱羧酶测定表明，与从生长培养基中清除的这些二胺的量相比，克氏锥虫的上鞭毛体阶段无法从头合成大量的腐胺和尸胺。放射性标记的腐胺很容易掺入亚精胺、精胺和锥虫特异性聚胺-谷胱甘肽缀合物锥硫酮（N-1, N-8-双（谷胱甘肽）亚精胺）中。同样，放射性标记的尸胺被掺入类似的多胺氨丙基尸胺、双(氨丙基)尸胺和另一种主要的未鉴定成分中。随后的研究表明，该主要成分是一种新型的聚胺-硫醇缀合物，其结构经化学合成证实为N-1,N-9-双(谷胱甘肽)氨丙基尸胺(高锥硫酮)。使用重组 T. cruzi 锥硫酮还原酶进行的动力学分析表明，该酶很容易还原高锥硫酮二硫化物，其动力学参数与二硫化锥硫酮相似，表明它是体内的生理底物。因此，克氏锥虫的表鞭毛体形式与非洲锥虫和利什曼原虫有显着不同，因为（a）无法从头合成大量的二胺，（b）将大量的腐胺和尸胺分别转化为精胺和双（氨丙基）尸胺，以及（c）合成高锥虫硫酮的能力以及 锥硫酮。讨论了这些发现对恰加斯病前瞻性化疗的影响。
Radiolabelling studies using tritiated ornithine, arginine and lysine, together with the relevant amino acid decarboxylase enzyme assays, indicate that the epimastigote stage of Trypanosoma cruzi is unable to synthesise significant amounts of putrescine and cadaverine de novo, compared to the amounts of these diamines scavenged from the growth medium. Radiolabelled putrescine is readily incorporated into spermidine, spermine and the trypanosomatid-specific polyamine-glutathione conjugate trypanothione (N-1, N-8-bis(glutathionyl)spermidine). Likewise, radiolabelled cadaverine is incorporated into the analogous polyamines aminopropylcadaverine, bis(aminopropyl)cadaverine and another major unidentified component. Subsequent studies showed this major component to be a novel polyamine-thiol conjugate whose structure was confirmed by chemical synthesis to be N-1,N-9-bis(glutathionyl)aminopropylcadaverine (homotrypanothione). Kinetic analyses using recombinant T. cruzi trypanothione reductase demonstrated that homotrypanothione disulphide is readily reduced by this enzyme with kinetic parameters similar to trypanothione disulphide, suggesting that it is a physiological substrate in vivo. Thus the epimastigote form of T. cruzi differs significantly from the African trypanosomes and Leishmania in (a) being unable to synthesise significant amounts of diamines de novo, (b) converting significant amounts of putrescine and cadaverine to spermine and bis(aminopropyl)cadaverine, respectively and (c) the ability to synthesise homotrypanothione as well as trypanothione. The implications of these findings with respect to the prospective chemotherapy of Chagas' disease are discussed.