BIOCHEMISTRY OF TRYPANOSOMATIDS - BASIS FOR DRUG DESIGN

为了合理设计治疗锥虫病的新药，我们 一直在探索增加锥虫体内氧化剂含量的方法 压力或对氧化剂的敏感性。 我们的研究包括 在锥虫体内产生自由基， 锥虫必须对抗氧化应激。 在上一次赠款期间， 期间，我们研究了以下内容：1）一个大系列的醌 合成了衍生物，并发现其在体外具有杀锥虫作用， 在体内没有任何活性。 试图修改结构，以防止 新陈代谢没有成功。 2)T. brucei、T. cruzi，C.束状， L.发现热带植物具有含铁的超氧化物歧化酶（SOD） 与哺乳动物细胞中发现的Cu，Zn-SOD和Mn-SOD相反。 一 对各种抑制剂的敏感性差异表明， 能够选择性地干扰这种关键酶。 3)在 与先前研究的所有其它生物的GSH还原酶相反， 锥虫酶对一种新 含巯基辅因子。 这个辅因子的结构， 锥虫硫酮，最近已被阐明，并发现是 双-（谷胱甘肽）亚精胺。 由于锥虫硫酮存在于所有的寄生锥虫中，例如T. brucei、T.克鲁济湖而不是在其他生物中，它提供了一个 化疗干预的独特攻击点。 据此在 在下一个资助期内，我们会集中研究这项新发现。 1)进一步 计划对锥虫硫酮进行化学和生物化学研究， 对分子的构象有了新的认识。 这些正在 追求，以便可以设计新的代理人， 的co-factor。 2)锥硫酮还原酶。fasciculata和T. 将对布鲁氏菌进行分离和研究，以便设计新的药剂， 来抑制这种关键酶 3)的生物合成 锥虫硫酮也提供了一个攻击点。 亚精胺类似物将 作为潜在的代理商。 希望这些研究能提供新的 对锥虫病药物设计深入了解。

In an attempt to rationally design new drugs for trypanosomiasis, we have been exploring ways to increase in trypanosomes the amount of oxidant stress or the sensitivity to oxidants. Our studies have included ways to generate free radicals in the trypanosome and the nature of the enzymes that trypanosomes have to combat oxidant stress. During the previous grant period, we have investigated the following: 1) A large series of quinone derivatives were synthesized and found to be trypanocidal in vitro but without any activity in vivo. Attempts to modify the structure to prevent metabolism were without success. 2) T. brucei, T. cruzi, C. fasciculata, L. tropica were found to have an iron-containing superoxide dismutase (SOD) in contrast to the Cu, Zn-SOD and Mn-SOD found in mammalian cells. A difference in sensitivity to various inhibitors points to the potential of being able to selectively interfere with this crucial enzyme. 3) In contrast to the GSH reductase from all other organisms previously studied, the trypanosomal enzyme had an obligate requirement for a novel thiol-containing co-factor. The structure of this co-factor, trypanothione, has been recently elucidated and found to be bis-(glutathionyl) spermidine. Since trypanothione is present in all the parasitic trypanosomes, e.g. T. brucei, T. cruzi, L. mexicana and not in other organisms, it offers a unique point of attack for chemotherapeutic intervention. Accordingly, in the next grant period, we will concentrate on this new finding. 1) Further chemical and biochemical studies of trypanothione are planned in order to gain new insight in the conformation of the molecule. These are being pursued so that new agents can be designed which will react to inactivate the co-factor. 2) Trypanothione reductase from C. fasciculata and T. brucei will be isolated and studied so that new agents can be designed and synthesized to inhibit this key enzyme. 3) The biosynthesis of trypanothione also offers a point of attack. Spermidine analogues will be evaluated as potential agents. Hopefully, these studies will give new insight into drug design for trypanosomiasis.