Podorvanov V V, Polishchuk A V, Zolotareva E K
Biofizika. 2007 Nov-Dec;52(6):1049-53.
It was shown that the light-dependent proton uptake by a suspension of isolated chloroplasts was completely inhibited in the presence of 30-50 microM Cu2+ ions at the 0.1-0.3 Cu2+/Chl ratio. At the same time, the rate of photosynthetic oxygen evolution in the presence of 30-200 microM CuSO4 was reduced by no more than 20-30% of control and up to 50% of the control DeltapH value was retained. The results allow us to suppose that, in the presence of copper ions: 1) electron transport in PS2 is inhibited at the level of the secondary quinone acceptor Q(B) whose photoreduction is accompanied by proton uptake from external medium; and 2) an alternative pathway of electron transfer to terminal acceptor is activated, which provides the photooxidation of water and the formation of transmembrane proton gradient.
结果表明，在0.1 - 0.3 Cu²⁺/Chl比例下，当存在30 - 50微摩尔/升的Cu²⁺离子时，分离叶绿体悬浮液的光依赖质子摄取被完全抑制。同时，在存在30 - 200微摩尔/升硫酸铜的情况下，光合放氧速率降低不超过对照的20 - 30%，并且保留了高达对照ΔpH值50%的水平。这些结果使我们推测在铜离子存在的情况下：1）PS2中的电子传递在次级醌受体Q(B)水平受到抑制，其光还原伴随着从外部介质摄取质子；2）一条通向末端受体的替代电子传递途径被激活，这使得水发生光氧化并形成跨膜质子梯度。
