静息和凝血酶刺激的人血小板中的磷酸肌醇代谢。反对代谢异质性的证据。

Phosphoinositide metabolism in resting and thrombin-stimulated human platelets. Evidence against metabolic heterogeneity.

作者信息

Tysnes O B, Verhoeven A J, Aarbakke G M, Holmsen H

出版信息

FEBS Lett. 1987 Jun 22;218(1):68-72. doi: 10.1016/0014-5793(87)81020-7.

Abstract

The specific radioactivity of the phosphodiester and phosphomonoester moieties of the phosphoinositides was determined in resting and thrombin-stimulated platelets that were prelabelled with [32P] Pi. In the unstimulated cells, the specific radioactivity of the monoester phosphates of PIP and PIP2 was similar. Both prolonged incubation at 37 degrees C and upon stimulation with 0.5 U/ml of thrombin, the specific radioactivity of the monoester phosphates decreased 10-15% in both polyphosphoinositides. In the unstimulated cells, the specific radioactivity of the diester phosphates was similar in PI, PIP and PIP2 but amounted only to 3% of the activity of the monoester groups. Prolonged incubation of the unstimulated cells as well as stimulation with thrombin induced a similar 5-6 fold increase in specific radioactivity of the diester phosphate of PI, PIP and PIP2. The results indicate that the phosphoinositides in both resting and thrombin-stimulated platelets exist in a metabolically homogeneous pool.

摘要

用[32P]Pi预标记静止和凝血酶刺激的血小板后，测定磷脂酰肌醇磷酸二酯和磷酸单酯部分的比放射性。在未刺激的细胞中，PIP和PIP2的磷酸单酯的比放射性相似。在37℃下长时间孵育以及用0.5U/ml凝血酶刺激后，两种多磷酸肌醇中磷酸单酯的比放射性均降低10 - 15%。在未刺激的细胞中，PI、PIP和PIP2中磷酸二酯的比放射性相似，但仅为磷酸单酯基团活性的3%。未刺激细胞的长时间孵育以及凝血酶刺激均导致PI、PIP和PIP2的磷酸二酯的比放射性增加约5 - 6倍。结果表明，静止和凝血酶刺激的血小板中的磷脂酰肌醇都存在于代谢均匀的池中。