La3+离子对叶绿体CF1-ATPase活力影响研究

为进一步弄清La3+离子对光合磷酸化及Hill反应影响作用机制,采用分光光度法,控制反应液中La3+离子浓度在0～20μmol.L-1范围,对纯化的游离态CF1-ATPase水解ATP活性测定结果表明:La3+离子对CF1-ATPase具有明显的促进作用。而且随La3+离子浓度增大,CF1-ATPase活性动力学曲线明显呈现"S"型。但当La3+离子浓度大于25μmol.L-1之后,La3+离子对游离态CF1-ATPase则表现出一定的抑制作用。而La3+离子浓度在0～30μmol.L-1范围内,受La3+离子作用类囊体膜CF1-ATPase活性动力学曲线则呈现双"S"形曲线。热稳定性实验结果表明:La3+离子可以降低CF1-ATPase活化能,提高CF1-ATPase的热稳定性。La3+离子对CF1-ATPase活性的影响可能与CF1-ATPase分子上别构位点有关,这也可能是La3+离子促进叶绿体Hill反应的关键部位。

Influence of La3+ Ions on Activity of Chloroplast CF1-ATPase

The results showed that 0~20 μmol · L-1 concentration range of La3+ ion on the heat-DTT activated soluble CF1-ATPase activity in pre-columri prior had obviouly stimulative effect.And with La3+ ion concentration increased,CF1-ATPase kinetic curve obviouly appears "S" model.But when La3+ ion concentration in more than 25 μmol · L-1,La3+ to the heat-DTT activation soluble ATPase showed certain inhibition.And La3+ concentration in 0~30 μmol · L-1 range,La3+ ion thick on the heat-DTT activation of thylakoid membrane bound CF1-ATPase activity kinetic curve revealed a double "S" shape curve.The scope of the activity test results showed that the La3+ ion could reduce CF1-ATPase activation energy,and improve CF1-ATPase thermal stability.La3+ for heat-DTT activation of the soluble CF1-ATPase,as well as on thylakoid membrane bound CF1-ATPase active effects might CF1-ATPase molecular allosteric site on relevant.And La3+ ion might be the key point to promote Hill reaction of chloroplast.But also may be La3+ ion promote chloroplast of the key parts of the Hill reaction.