Seehra J S, Jordan P M, Akhtar M
Biochem J. 1983 Mar 1;209(3):709-18. doi: 10.1042/bj2090709.
An improved method for the preparation of various species of porphobilinogen stereospecifically labelled with 3H in the side chains (at C-6, C-7 and C-8) is described. These labelled samples were used to study the mechanism and stereochemistry of anaerobic as well as aerobic coproporphyrinogen III oxidase of light-grown Rhodopseudomonas spheroides. It was shown that both the oxidases catalyse the conversion of the propionate side chains of coproporphyrinogen III into the vinyl groups of protoporphyrinogen IX, (formula; see text) with the labilization of the pro-S-hydrogen atom at the beta-position. These results are similar to those previously recorded for such conversions in animal and plant systems. In the light of the cumulative information available to date, mechanisms for the conversion, (formula; see text) are discussed and doubt is cast on the participation of hydroxylated intermediates in the process.
本文描述了一种改进的方法，用于制备在侧链（C-6、C-7和C-8）上用³H立体定向标记的各种卟啉胆色素原。这些标记样品用于研究光合球形红假单胞菌厌氧和好氧粪卟啉原III氧化酶的作用机制和立体化学。结果表明，这两种氧化酶都催化粪卟啉原III的丙酸侧链转化为原卟啉原IX的乙烯基（化学式；见正文），同时使β位的前-S-氢原子不稳定。这些结果与之前在动物和植物系统中此类转化的记录相似。根据目前可获得的累积信息，讨论了转化的机制（化学式；见正文），并对羟基化中间体在此过程中的参与提出了质疑。
