通过 c(4)植物的磷酸烯醇丙酮酸羧化酶对碳同位素进行酶促分级分离。
Enzymatic fractionation of carbon isotopes by phosphoenolpyruvate carboxylase from c(4) plants.
机构信息
Department of Oceanography, Texas A & M University, College Station, Texas 77843.
出版信息
Plant Physiol. 1973 Jun;51(6):1051-4. doi: 10.1104/pp.51.6.1051.
The carbon atoms of glucose and malate in C(4) plants are 2 to 3 per thousand enriched in (12)C with respect to atmospheric CO(2); whereas these intermediates in C(3) plants are 15 to 18 per thousand enriched with (12)C with respect to atmospheric CO(2). The enzymatic synthesis of malate from phosphoenolpyruvate and bicarbonate in preparations of leaves of Sorghum bicolor, Haygrazer result in a carbon isotope fractionation of about 3 per thousand. The enzymatic synthesis of phosphoglyceric acid from ribulose 1,5-diP and CO(2) in these preparations (contaminated with carbonic anhydrase) at 24 C and 37 C result in a carbon isotope fractionation of 33.7 per thousand and 18.3 per thousand, respectively. These data are consistent with the conclusion that the small enrichment of (12)C in the carbon atoms of malate and glucose (with respect to atmospheric CO(2)) in leaves of Sorghum bicolor, Haygrazer occurs at the phosphoenolpyruvate carboxylase step.
C(4) 植物中的葡萄糖和苹果酸中的碳原子相对于大气中的 CO(2)，(12)C 的丰度富集了 2 到 3 个千分位；而 C(3) 植物中的这些中间产物相对于大气 CO(2)，(12)C 的丰度富集了 15 到 18 个千分位。在 Sorghum bicolor、Haygrazer 的叶片制备物中，从磷酸烯醇丙酮酸和碳酸氢盐酶促合成苹果酸，导致大约 3 个千分位的碳同位素分馏。在这些制备物中（含有碳酸酐酶），在 24°C 和 37°C 下，从核酮糖 1,5-二磷酸和 CO(2)酶促合成磷酸甘油酸，导致碳同位素分馏分别为 33.7 个千分位和 18.3 个千分位。这些数据与以下结论一致，即在 Sorghum bicolor、Haygrazer 的叶片中，苹果酸和葡萄糖中的碳原子（相对于大气 CO(2)）的 (12)C 轻微富集发生在磷酸烯醇丙酮酸羧化酶步骤。
Zotero 插件