BIOSYNTHESIS OF TAXOL AND RELATED COMPOUNDS

从短叶红豆杉等植物中分离得到的二萜类化合物紫杉醇 红豆杉属植物，是一种重要的抗癌新药。一直以来 被FDA批准用于治疗卵巢癌，也显示出希望 治疗乳腺癌、肺癌和其他癌症。泰索帝，一种半合成类似物， 也在进行临床评估，到目前为止，结果很好。 这些临床上的成功提出了确保足够的 这些药物的商业供应。这些结构的复杂性 对于经济上可行的这些药物的全合成来说，这不是一个好兆头， 甚至在即将更换新的树皮提取液之后 半合成从更丰富的紫杉烷，10-脱乙酰巴卡汀-III，如 商业来源的紫杉醇，这些和后代的供应 紫杉烷类药物将依赖于至少 官能化紫杉烷环系统在未来几年。 这是这个项目的长期目标是澄清，在化学， 酶，最终，遗传水平，生物合成途径，通过它 紫杉醇和相关的紫杉烷是在红豆杉工厂组装的。我们建议 (1)建立紫杉烷环系的形成模式 推测的前体，香叶基焦磷酸，(2)映射序列 从最初的碳氢化合物前体到完全的 紫杉醇的官能化紫杉烷部分，(3)获得机理洞察 苯丙氨酸转化为苯异丝氨酸和苯甲酸酯 紫杉醇的部分组成和(4)确定了紫杉醇附着的模式和阶段 C-13侧链到环系并分离酶(S)催化 这一过程。作为这些研究的工具，我们还将开发和 优化红豆杉细胞培养，使紫杉烷产量达到 生物合成实验。 预计生成的信息将有助于提供 努力开发替代生物技术的知识库 这些重要新抗肿瘤药物的商业化生产工艺 毒品。

Taxol, a diterpene derivative isolated from Taxus brevifolia and other Taxus species, is an important new anti-cancer agent. It has been approved by the FDA for treatment of ovarian cancer and also shows promise against breast, lung and other cancers. Taxotere, a semisynthetic analog, is also undergoing clinical evaluation with, so far, excellent results. These clinical successes have raised the problem of securing adequate commercial supplies of these drugs. The complexity of the structures does not bode well for an economically viable total synthesis of these drugs, and even after the imminent replacement of new bark extraction by semisynthesis from a more abundant taxane, 10-deacetylbaccatin-III, as the commercial source of taxol, the supply of these and future generation taxane-based drugs will depend on biosynthesis of at least the functionalized taxane ring system for years to come. It is the long-term goal of this project to elucidate, at the chemical, enzymatic and eventually, genetic level, the biosynthetic pathway by which taxol and related taxanes are assembled in the yew plant. We propose to (1) establish the mode of formation of the taxane ring system from its presumed precursor, geranylgeranyl pyrophosphate, (2) map the sequence of reactions leading from the initial hydrocarbon precursor to the fully functionalized taxane moiety of taxol, (3) gain mechanistic insight into the transformation of phenylalanine into the phenylisoserine and benzoate moieties of taxol and (4) confirm the model and stage of attachment of the C-13 side chain to the ring system and isolate the enzyme(s) catalyzing this process. As a tool for these studies we will also develop and optimize Taxus cell cultures to levels of taxane production useful for biosynthetic experiments. It is anticipated that the information generated will help provide the knowledge base for efforts to develop alternative biotechnological processes for the commercial production of these important new antitumor drugs.