Mattheis J R, Rebeiz C A
J Biol Chem. 1977 Jun 25;252(12):4022-4.
Developing chloroplasts were isolated from greening Cucumis cotyledons in a cofactor-enriched medium and were incubated in the dark with 14C-labeled and unlabeled magnesium-protoporphyrin monoester. The metabolic pools between protoporphyrin and protochlorophyllide were monitored spectrofluorometrically. The incorporation of the 14C label into protochlorophyllide was also determined. It was shown that magnesium-protoporphyrin monoester, a postulated intermediate of the chlorphyll biosynthetic pathway, was convertible into protochlorophyllide with relatively high yields. Since protochlorophyllide is the immediate precursor of chlorophyll a it was concluded that magnesium-protoporphyrin monoester was indeed an intermediate of the chlorophyll biosynthetic pathway.
从正在变绿的黄瓜子叶中分离出发育中的叶绿体，置于富含辅因子的培养基中，并在黑暗中与14C标记和未标记的单酯镁原卟啉一起孵育。用荧光分光光度法监测原卟啉和原叶绿素酸酯之间的代谢库。还测定了14C标记掺入原叶绿素酸酯的情况。结果表明，单酯镁原卟啉是叶绿素生物合成途径中假定的中间体，它可以以相对较高的产率转化为原叶绿素酸酯。由于原叶绿素酸酯是叶绿素a的直接前体，因此得出结论，单酯镁原卟啉确实是叶绿素生物合成途径的中间体。
