Dale G L
Blood. 1985 Nov;66(5):1133-7.
The human erythrocyte actively phosphorylates and dephosphorylates phosphatidylinositol present in the membrane in an apparent "futile cycle." Recent reports have proposed that this phosphorylation/dephosphorylation cycle is a significant consumer of adenosine-5'-triphosphate (ATP) in the erythrocyte. This study details two independent techniques for quantitating the ATP consumed by this phosphoinositide futile cycle. With the first technique a quasi-steady-state labeling of erythrocyte ATP with 32P-phosphate was obtained, and the rate of synthesis of 32P-phosphoinositides was then monitored. The second technique used a novel labeling strategy that allowed only ATP to be labeled with 32P; the transfer of 32P from ATP to phosphoinositides was then an independent measure of the ATP consumed for phosphoinositide synthesis. These two techniques documented that 0.5% to 1.0% of net ATP produced by the erythrocyte is used for phosphoinositide synthesis.
人类红细胞能使存在于膜中的磷脂酰肌醇进行磷酸化和去磷酸化，这一过程明显呈现出“无效循环”。最近的报道提出，这种磷酸化/去磷酸化循环是红细胞中三磷酸腺苷（ATP）的一个重要消耗途径。本研究详细介绍了两种独立的技术，用于定量这种磷酸肌醇无效循环所消耗的ATP。第一种技术是用³²P-磷酸盐对红细胞ATP进行准稳态标记，然后监测³²P-磷酸肌醇的合成速率。第二种技术采用了一种新颖的标记策略，只允许ATP被³²P标记；然后将³²P从ATP转移到磷酸肌醇上，这是对磷酸肌醇合成所消耗ATP的一种独立测量方法。这两种技术证明，红细胞产生的净ATP中有0.5%至1.0%用于磷酸肌醇的合成。
