Radmer R, Ollinger O
Martin Marietta Laboratories, Baltimore, MD 21227, USA.
FEBS Lett. 1986 Jan;195(1-2):285-9. doi: 10.1016/0014-5793(86)80178-8.
A modified mass spectrometer was used to determine whether the higher oxidation states of the photosynthetic O2-evolving system contain substrate water that is not freely exchangeable with the external medium. Our data indicated that the higher oxidation states contain no appreciable bound, non-exchangeable H2O. This suggests that H2O oxidation takes place via a rapid, concerted, all-or-none mechanism rather than by a mechanism involving stable, partially oxidized, H2O-derived intermediates. These findings set definite constraints on possible mechanisms of O2 evolution.
使用一台改良的质谱仪来确定光合放氧系统的较高氧化态是否含有与外部介质不能自由交换的底物水。我们的数据表明，较高氧化态不含有明显的结合态、不可交换的H₂O。这表明H₂O氧化是通过一种快速、协同、全或无的机制进行的，而不是通过涉及稳定的、部分氧化的、源自H₂O的中间体的机制。这些发现对O₂进化的可能机制设定了明确的限制。
