In the biosynthetic pathway of bacteriochlorophyll(BChl)-a/b/c/d/e molecules, BchF and BchV enzymes catalyze the hydration of a C3-vinyl to C3-1-hydroxyethyl group. In this study, the in vitro reactions catalyzed by BchF and BchV partially afforded a C3¹-epimeric mixture of the hydrated products (secondary alcohols), with the primary recovery of the C3-vinylated substrate. The stereoselectivity and substrate specificity for the in vitro reverse enzymatic dehydration were examined using zinc chlorophyll analogs as model substrates by BchF and BchV, which were obtained from extracts of Escherichia coli overexpressing the respective genes from Chlorobaculum tepidum and used without further purification. Both BchF and BchV preferred dehydration of the (3¹R)-epimers over the (3¹S)-epimers. The (3¹R)-epimer was directly dehydrated by BchF and BchV to give the C3-vinylated product. By contrast, two reaction pathways for BchF and BchV dehydrations of the (3¹S)-epimer were proposed: (1) the (3¹S)-epimer would be directly dehydrated to C3-vinyl group. (2) the (3¹S)-epimer would be epimerized to the (3¹R)-epimer, and the resulting epimer was dehydrated. The results indicated that both BchF and BchV did function as a hydratase/dehydratase and could play a role in the C3¹-epimerization. An increase in the alkyl size at the C8-position gradually suppressed the BchF and BchV-catalyzed dehydration in vitro, while the C12¹- and C20-methylation only slightly affected the reaction. Using the BchF dehydration, a large amount of 3-vinyl-bacteriochlorophyllide-a was successfully prepared, with the retention of the chemically labile, central magnesium atom.

在细菌叶绿素(BChl) -a / b / c / d / e分子的生物合成途径中，BchF和BchV酶催化C3-乙烯基水化为C3-1-羟乙基。在这项研究中，由 BchF 和 BchV 催化的体外反应部分提供了 C3 ¹ -水合产物（仲醇）的差向异构混合物，并初步回收了 C3-乙烯基化底物。使用从大肠杆菌提取物中获得的 BchF 和 BchV，使用叶绿素锌类似物作为模型底物，检查了体外反向酶促脱水的立体选择性和底物特异性过表达来自Chlorobaculum tepidum的相应基因，无需进一步纯化即可使用。BchF 和 BchV 都优先于 (3 ¹ R )-差向异构体脱水，而不是 (3 ¹ S )-差向异构体。(3 ¹ R )-差向异构体通过 BchF 和 BchV 直接脱水得到 C3-乙烯基化产物。相比之下，提出了(3 ¹ S )-差向异构体BchF和BchV脱水的两条反应途径：(1) (3 ¹ S )-差向异构体直接脱水生成C3-乙烯基。(2) (3 ¹ S )-差向异构体将差向异构化为 (3 ¹ R)-差向异构体，并将所得差向异构体脱水。^{结果表明，BchF 和 BchV 均作为水合酶/脱水酶发挥作用，并可在 C3 1} -差向异构化中发挥作用。C8 位烷基大小的增加逐渐抑制 BchF 和 BchV 催化的体外脱水，而 C12 ^1-和 C20- 甲基化仅轻微影响反应。使用 BchF 脱水，成功制备了大量 3-乙烯基-细菌叶绿素-a，并保留了化学不稳定的中心镁原子。