Biosynthesis of porphyrins and related macrocycles. Part 53. Stereochemical studies on the enzymic formation of hydroxymethylbilane, the precursor of uroporphyrinogen III
作者:Jean-Roch Schauder、Stefan Jendrezejewski、Werner L. Neidhart、Graham J. Hart、Alan R. Battersby
DOI:10.1039/a904261j
日期:——
A new synthesis of porphobilinogen 1 (PBG) is described that allows the preparation of (11R)-[11-3H1]PBG 1a and its (11S)-enantiomer 1b. Their enantiomeric purities are determined by degradation of their immediate synthetic precursors by way of 3H-labelled glycines to yield two samples of 3H-labelled glycolic acid 16. The enzyme glycolate oxidase, known to remove HR stereospecifically from the methylene
胆色素原1的新的合成(PBG)中描述,其允许的制备(11 - [R )- [11- 3 ħ 1 ] PBG 1a和它的(11小号) -对映体1B。它们的对映体纯度是通过3 H-标记的甘氨酸降解其直接合成前体以得到两个3 H-标记的乙醇酸16样品而确定的。乙醇酸氧化酶,已知可从乙醇的亚甲基立体定向去除H R。然后使用形成乙醛酸17中的酸来分析这两个样品的构型。各3个H标记的PBG 1a和1b被羟甲基胆烷合酶转化为羟甲基胆烷5a和5b。设计了用于从水中分离该不稳定产物并将其随后降解为乙醇酸的另外两个样品的方法。用酶法分析这些化合物以证明总体上保留了构型,因为PBG 1的氨基甲基碳通过酶提供了bilane 5的羟甲基中心。因此,在整个过程中形成的两个共价键必须都涉及保留配置或两者同时使用。讨论了这些结果的重要性。