Smilowitz H M, Aramli L, Xu D, Epstein P M
Department of Pharmacology, University of Connecticut Health Center, Farmington 06030.
Life Sci. 1991;49(1):29-37. doi: 10.1016/0024-3205(91)90576-w.
Using O-phosphotyrosine as a substrate, human platelets were shown to contain a highly active phosphotyrosine phosphatase (PTPase) activity. This activity was potently inhibited by vanadate, molybdate, and HgCl2. About 80% of the PTPase activity was particulate. When Triton-solubilized PTPase activity from whole platelets was applied to a DEAE Sephacel column about 40% came through unbound. The activity that bound was eluted by a NaCl gradient as a broad, heterogeneous peak. The possibility is raised for the existence of multiple forms of phosphotyrosine phosphatases in human platelets. That one or more of these forms may be regulated by activators of platelet aggregation and secretion, such as thrombin and collagen, is discussed.
以O-磷酸酪氨酸作为底物时，发现人血小板含有高活性的磷酸酪氨酸磷酸酶（PTPase）活性。该活性受到钒酸盐、钼酸盐和HgCl2的强烈抑制。约80%的PTPase活性存在于颗粒部分。当将经Triton增溶的全血小板PTPase活性应用于DEAE Sephacel柱时，约40%的活性未结合而直接通过。结合的活性通过NaCl梯度洗脱，呈现为一个宽的、异质性的峰。由此提出人血小板中可能存在多种形式的磷酸酪氨酸磷酸酶。本文还讨论了这些形式中的一种或多种可能受血小板聚集和分泌激活剂（如凝血酶和胶原）调控的可能性。
