无机磷影响叠氮钠对ATP合成酶合成活性的抑制  

The Effects of P_i on the Inhibition of ATP Synthesis Activity of F_1F_O-ATPase by Azide

作　　者：蒙昔[1] 李生广[1] 林治焕[1] 

机构地区：[1]中国科学院生物物理研究所,北京100101

出　　处：《生物化学与生物物理进展》2001年第6期885-889,共5页Progress In Biochemistry and Biophysics

基　　金：国家自然科学基金 (39670 1 83);北京大学蛋白质工程及植物基因工程国家重点实验室基金资助项目~~

摘　　要：利用ADP和放射性磷直接合成ATP的方法 ,研究了无机磷 (Pi)和叠氮钠对猪心线粒体ATP合成酶(F1FO ATPase)ATP合成活性的影响 .结果发现无机磷除作为合成ATP的底物参与F1FO ATPase的合成反应外 ,还对F1FO ATPase的合成活性呈现抑制作用 ,在 1mmol/LADP存在时 ,随着Pi 浓度由 0 0 1～ 10mmol/L增加 ,抑制合成作用越来越强 .与叠氮钠在低浓度时 (小于 1mmol/L)只抑制ATP水解 ,不影响ATP合成的观点不同 .实验结果显示 0 1mmol/L叠氮钠表观激活F1FO ATPase的ATP合成活性 ,且激活程度与反应体系中所加Pi 的浓度呈负相关 .当固定Pi 浓度 (0 1mmol/L)后 ,随着叠氮钠浓度的增加表观激活程度也在变化 ,叠氮钠与磷浓度相等时表观激活程度最大 ,直至叠氮钠浓度接近 0 5mmol/L时 ,开始呈现表观抑制现象 ,叠氮钠浓度高于 1mmol/L之后 。Using ATP directly synthetical method with ADP and radiophosphate, the effects of azide and inorganic phosphate on the ATP synthesis of F1F0-ATPase from pig heart mitochondria are investigated. It is found that P-i not only takes an active part in ATP synthesis as a substrate, but also has an inhibition effect on ATP synthesis of F1F0-ATPase. In the presence of 1 mmol/L ADP the inhibition increases with the increase of P-i concentration from 0.01 mmol/L to 10 mmoL/L. The viewpoint is different from that azide only inhibites ATP hydrolysis but not affects the ATP synthesis at low concentration (<1 mmol/L). The results indicate that 0.1 mmol/L azide apparently activates ATP synthesis of F1F0-ATPase. The activation is negatively related to the concentration of P-i in the reaction system. When the concentration of P-i is kept at 0.1 mmol/L, with the increase of azide concentration, the apparent activation degree of ATP synthesis by azide is changed. When the concentrations of azide and P-i are equal, the apparent activation by azide is the biggest. The apparent inhibition of ATP synthesis by azide would not begin until the concentration of azide reaches near 0.5 mmol/L. After the concentration of azide is higher than 1 mmol/L, the uncoupling of F1F0-ATPase appears. The mechanism of the roles of azide and P-i is discussed.

关 键 词：F1FO-ATPase ATP合成酶 叠氮钠 无机磷 线粒体 合成活性 抑制 

分 类 号：Q244[生物学—细胞生物学] Q559