Osei A A, Everett G W, Himes R H
Department of Biochemistry, University of Kansas, Lawrence 66045.
Biochim Biophys Acta. 1988 Jul 20;955(2):269-71. doi: 10.1016/0167-4838(88)90202-6.
Tubulin assembly was conducted in [18O]H2O and the resulting mixture of GTP, GDP and Pi was examined by 31P-NMR. Two Pi signals, separated by about 0.02 ppm, were observed. By combining this mixture with a solution of Pi containing all five possible 16O and 18O isotopomers of Pi, it was shown that the two signals were due to [16O4]- and [16O3, 18O]Pi. The amount of 18O incorporated into the Pi was that expected if the hydrolysis of GTP during tubulin assembly occurs with cleavage of the gamma-phosphorus-bridge oxygen bond.
微管蛋白组装在[18O]H2O中进行，通过31P-NMR检测所得的GTP、GDP和Pi混合物。观察到两个Pi信号，其间隔约为0.02 ppm。将该混合物与含有Pi的所有五种可能的16O和18O同位素异构体的溶液混合，结果表明这两个信号分别归因于[16O4]-Pi和[16O3, 18O]Pi。如果微管蛋白组装过程中GTP的水解是通过γ-磷桥氧键的断裂发生的，那么掺入到Pi中的18O量符合预期。
