Murata K, Sakon M, Kambayashi J, Yukawa M, Ariyoshi H, Shiba E, Kawasaki T, Kang J, Mori T
Department of Surgery II, Osaka University Medical School, Japan.
Biochem Int. 1992 Feb;26(2):327-34.
Okadaic acid and calyculin A, specific and cell permeable inhibitors of protein phosphatase 1 and 2A, inhibited aggregation, secretion and delta [Ca++]i in thrombin stimulated platelets. The inhibitory effect of calyculin A (IC50: 3.6-4.8nM) was about two hundred times more potent than that of okadaic acid (IC50: 0.8-1.3 microM), which is consistent with the difference of the reported Ki values for protein phosphatase 1. These phosphatase inhibitors and PGI2 synergistically enhanced the phosphorylation of 50kDa protein (P50), which is solely related to the inhibition of platelet reaction. These results indicate that serine/threonine protein phosphatase 1 might play a role in platelet activation.
冈田酸和花萼海绵诱癌素A是蛋白磷酸酶1和2A的特异性细胞可渗透抑制剂，它们可抑制凝血酶刺激的血小板的聚集、分泌及细胞内钙离子浓度变化（δ[Ca++]i）。花萼海绵诱癌素A的抑制作用（半数抑制浓度：3.6 - 4.8纳摩尔）比冈田酸（半数抑制浓度：0.8 - 1.3微摩尔）强约200倍，这与报道的蛋白磷酸酶1的抑制常数（Ki）值的差异一致。这些磷酸酶抑制剂与前列环素（PGI2）协同增强了50kDa蛋白（P50）的磷酸化，这仅与血小板反应的抑制有关。这些结果表明丝氨酸/苏氨酸蛋白磷酸酶1可能在血小板激活中发挥作用。
