Incorporation of atmospheric oxygen into the carbonyl functionality of the protochlorophyllide isocyclic ring.
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.
Publication Source (Journal or Book title)
The Biochemical journal
Walker, C., Mansfield, K., Smith, K., & Castelfranco, P. (1989). Incorporation of atmospheric oxygen into the carbonyl functionality of the protochlorophyllide isocyclic ring.. The Biochemical journal, 257 (2), 599-602. https://doi.org/10.1042/bj2570599