Jajoo Anjana, Bharti Sudhakar, Kawamori Asako
School of Life Sciences, Devi Ahilya Vishwavidyalaya, Vigyan Bhawan, Khandwa Road, Indore 452 017, India.
J Bioenerg Biomembr. 2005 Feb;37(1):49-54. doi: 10.1007/s10863-005-4123-0.
Chloride is required for the maximum activity of the oxygen evolving complex (OEC) while formate inhibits the function of OEC. On the basis of the measurements of oxygen evolution rates and the S(2) state multiline EPR signal, an interaction between the action of chloride and formate at the donor side of PS II has been suggested. Moreover, the Fe(2)+Q-A EPR signals were measured to investigate a common binding site of both these anions at the PS II acceptor side. Other monovalent anions like bromide, nitrate etc. could influence the effects of formate to a small extent at the donor side of PS II, but not significantly at the acceptor side of PS II. The results presented in this paper clearly suggest a competitive binding of formate and chloride at the PS II acceptor side.
氯离子是使放氧复合体（OEC）发挥最大活性所必需的，而甲酸盐会抑制OEC的功能。基于对放氧速率和S(2)态多线电子顺磁共振（EPR）信号的测量，有人提出在光系统II（PS II）供体侧，氯离子和甲酸盐的作用之间存在相互作用。此外，还测量了Fe(2)+Q-A EPR信号，以研究这两种阴离子在PS II受体侧的共同结合位点。其他单价阴离子，如溴离子、硝酸根离子等，在PS II供体侧对甲酸盐的影响有一定程度的作用，但在PS II受体侧作用不显著。本文给出的结果清楚地表明，在PS II受体侧，甲酸盐和氯离子存在竞争性结合。
