MARINE CHEMISTRY WITH SPECIAL EMPHASIS ON STEROIDS

直到最近，进行生物合成实验一直很困难。 关于带有标记前体的海绵代谢物。我们现在已经解决了大部分 与这项工作相关的技术问题，并打算在 详细描述了许多不寻常类型的甾醇结构的生物合成 在过去的十年里，在低等海洋动物中都遇到过这种情况。这个 下面的生物合成途径将用放射性方法进行检查 标记的甾醇前体，它将专门为这些 用途：(A)高度烷基化的甾醇侧链的生物合成方式 由三重和四重生物甲基化产生；(B)生物合成 许多新的含有环丙基的甾醇侧链，它们只存在于 海洋生物；(C)独特的24-去甲甾醇和 27-去甲基麦角甾烷-一组甾醇，其中末端甲基 胆固醇丢失；(D)环丙烯侧基的生物合成 链--海绵甾醇的另一个独特结构特征；(E) 19-去甲肾上腺素的生物合成--一组海绵甾醇 它们的细胞核与目前使用的口服避孕药相似；(F)程度 低等海洋动物中甾醇的从头生物合成；(G) 共生菌等单细胞生物在甾醇生物合成中的应用 完整的和无细胞的系统。

Until recently, it has been difficult to conduct biosynthetic experiments on sponge metabolites with labelled precursors. We have now solved most of the technical problems associated with such work and intend to study in detail the biosynthesis of the many unusual types of sterol structures that have been encountered during the past decade in lower marine animals. The following biosynthetic pathways will be examined using radioactively labelled sterol precursors, which will be specially synthesized for these purposes: (a) mode of biosynthesis of highly alkylated sterol side chains resulting from triple and quadruple biomethylation; (b) biosynthesis of the many novel cyclopropyl-containing sterol side chains, which occur solely in marine organisms; (c) origin of the unique 24-nor-sterols and 27-norergostanes - a group of sterols in which the terminal methyl group of cholesterol is lost; (d) biosynthesis of cyclopropene-containing side chains - another unique structural feature of sponge sterols; (e) biosynthesis of 19-nor sterols - a group of sponge sterols which in terms of their nuclei resemble the currently used oral contraceptives; (f) extent of de novo biosynthesis of sterols in lower marine animals; (g) role of symbionts and other unicellular organisms in sterol biosynthesis using intact as well as cell-free systems.