BIOCHEMISTRY OF TRYPANOSOMATIDS - BASIS FOR DRUG DESIGN

为了合理设计治疗锥虫病的新药，我们已经 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。我们的研究包括如何 锥虫体内产生自由基及其酶的性质 锥虫必须抵抗氧化应激。在上一次拨款期间 期间，我们研究了以下几个方面：1)大系列的苯二酚 合成的衍生物在体外被发现是杀锥虫的，但 在体内没有任何活动。尝试修改结构以防止 新陈代谢没有成功。2)布氏锥虫(T.brucei)、克氏锥虫(T.ruzi)、簇毛锥虫(C.Fasculata)、 热带乳杆菌含有一种含铁的超氧化物歧化酶(SOD)。 与哺乳动物细胞中发现的铜、锌-超氧化物歧化酶和锰-超氧化物歧化酶形成对比。一个 对不同抑制剂的敏感性差异表明， 能够选择性地干扰这种关键的酶。3)在 与之前研究的所有其他生物的GSH还原酶不同， 锥体酶对一种新的 含硫醇的辅因子。这个辅因子的结构， 台盼硫酮，最近被阐明并发现 双(谷胱甘肽)亚精胺。 由于锥硫素存在于所有寄生的锥虫体内，如锥虫T. Brucei，T.ruzi，L.miciana，而不是在其他生物体中，它提供了一种 独特的化疗介入攻击点。因此，在 在下一个授权期，我们将集中精力研究这一新发现。1)进一步 计划对台盼硫酮进行化学和生化研究，以便 对分子构象有了新的认识。这些都是 这样就可以设计出对灭活做出反应的新的代理 辅助性因素。(2)丛枝锥虫和丛枝锥虫的锥硫酮还原酶。 布鲁赛病毒将被分离和研究，以便设计和开发新的药物 合成以抑制这一关键酶。3)生物合成 锥虫硫酮也提供了一个攻击点。亚精胺类似物将是 被评估为潜在的代理人。希望这些研究将给出新的 对锥虫病药物设计的洞察。

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.