Walker C J, Mansfield K E, Smith K M, Castelfranco P A
Department of Botany, University of California, Davis 95616.
Biochem J. 1989 Jan 15;257(2):599-602. doi: 10.1042/bj2570599.
Detached cucumber (Cucumis sativus L. var. Beit Alpha) cotyledons incubated in darkness with 5-aminolaevulinic acid and either 16O2 air (control) or 18O2 in N2 accumulated protochlorophyllide. This was converted into methyl phaeoporphyrin alpha 5 and analysed by mass spectrometry. The molecular ion of the methyl phaeoporphyrin alpha 5 derived from the 18O2 incubation was 2 mass units greater than that of the control, establishing that the oxo oxygen atom of the isocyclic ring is derived from atmospheric oxygen.
将分离的黄瓜（Cucumis sativus L. var. Beit Alpha）子叶在黑暗中与5-氨基乙酰丙酸一起培养，并置于含有16O2的空气（对照）或N2中的18O2中，子叶积累了原叶绿素酸酯。将其转化为甲基脱镁叶绿酸α5并通过质谱分析。源自18O2培养的甲基脱镁叶绿酸α5的分子离子比对照的分子离子大2个质量单位，这表明异环的羰基氧原子来自大气中的氧气。
