萜烯生物合成的复杂机制属于天然产物化学中最具挑战性的问题。解决这些问题的方法包括萜烯合酶的基于结构的定点诱变,计算方法,和同位素标记实验。后一种方法在生物合成研究中有着悠久的传统,最近经历了复兴,在基因组测序后,能够快速获得生物合成基因和酶。今天,这允许一种组合方法,其中同位素标记的底物可以与重组萜合酶一起孵育。这些明确定义的反应设置可以为萜烯合酶催化的反应提供详细的机理见解,最近的发展大大加深了我们对萜烯生物合成的理解。本章将讨论最新技术,并介绍在萜烯合酶的机理研究中利用同位素标记的一些最重要的方法。
The intricate mechanisms in the biosynthesis of terpenes belong to the most challenging problems in natural product chemistry. Methods to address these problems include the structure-based site-directed mutagenesis of terpene synthases, computational approaches, and isotopic labeling experiments. The latter approach has a long tradition in biosynthesis studies and has recently experienced a revival, after genome sequencing enabled rapid access to biosynthetic genes and enzymes. Today, this allows for a combined approach in which isotopically labeled substrates can be incubated with recombinant terpene synthases. These clearly defined reaction setups can give detailed mechanistic insights into the reactions catalyzed by terpene synthases, and recent developments have substantially deepened our understanding of terpene biosynthesis. This chapter will discuss the state of the art and introduce some of the most important methods that make use of isotopic labelings in mechanistic studies on terpene synthases.