pH对大鼠棕色脂肪组织亚线粒体片段上解偶联蛋白与嘌呤核苷酸结合的影响

Effect of pH on Binding of Purine Nudeotides to Uncoupling Protein in Subnitochondrial Parti-cles from Rat Brown Adipose Tissue

用Lubrol和3 mol/L尿素对大鼠棕色脂肪组织线粒体进一步处理,以所形成的亚线粒体片段为标本,在不同pH下,各种嘌呤核苷酸与解偶联蛋白结合的pKd图显示,GDP和ADP与解偶联蛋白结合的pKd的峰值大约在pH5.5处,偏离此pH越多,pKd降低越甚;GTP和ATP与解偶联蛋白结合的pKd大约在pH小于5.5时最大并基本保持恒定,而大于此pH时,pKd迅速减低。pH一定时,GDP和GTP与解偶联蛋白结合的pKd分别大于ADP和ATP的pKd。

Using submitochondrial particles, from rat brown adipose tissue mitochondria treated by Lubrol and 3 mol/L urea, as a model, the relationship between different pH and pKd of binding of purine nucleotides to uncoupling protein was estimated. When it was shown as plots of pKd against pH, it was found that the pKd peak of binding of GDP or ADP to uncoupling protein was about pH 5.5. The greater pH deviated, the less pKd became. The highest pKd of binding of GTP or ATP to uncoupling protein was also near pH 5.5, below which pKd remained constant, but above which pKd dropped rapidly. At a certain pH, pKd of binding of GDP or GTP to uncoupling protein was higher than that of binding of ADP or ATP, respectively.