Radical S-adenosyl-l-methionine (SAM) enzymes belong to a family of catalysts whose number of annotated sequences is still growing. Upon the one-electron reduction of a [Fe₄S₄] cluster, they can cleave SAM to produce a highly reactive 5′-deoxyadenosyl radical species. This radical species in turn triggers a wide variety of radical-based reactions on substrates ranging from small organic molecules to proteins, DNA or RNA. The challenging reactions they catalyse makes them very promising catalysts for diverse biotechnological applications. However, the high-energy intermediates involved require fine control of the chemistry by the protein matrix. Understanding their control mechanism is a prerequisite for a broader use of these enzymes as synthetic tools. Here I review some of the latest developments in the field, focusing on the structure–function relationship of a few examples for which three-dimensional structures, in vitro and spectroscopic data, as well as theoretical calculations, are available to better describe the close interaction between the chemistry performed and the tight control of the protein matrix.

自由基S-腺苷-1-甲硫氨酸（SAM）酶属于一类催化剂，其带注释序列的数量仍在增长。在单电子还原[Fe ₄ S ₄簇，它们可以裂解SAM产生高反应性的5'-脱氧腺苷基团。反过来，这种自由基会在底物上引发各种基于自由基的反应，从小的有机分子到蛋白质，DNA或RNA。它们催化的挑战性反应使其成为用于多种生物技术应用的非常有希望的催化剂。但是，涉及的高能中间体需要通过蛋白质基质很好地控制化学反应。了解它们的控制机制是广泛使用这些酶作为合成工具的前提。在这里，我将回顾该领域的一些最新进展，重点关注几个实例的结构与功能关系，这些实例具有三维结构，体外和光谱数据以及理论计算，