Semagacestat（司马西特，LY-450139，LY450139）是⼀种有效和选择性γ-secretase（γ-分泌酶）抑制剂，γ分泌酶是一种内膜切割天冬氨酸蛋白酶（intramenbrane-cleaving aspartyl protease），切割许多I型膜蛋白，在基于膜和细胞的γ分泌酶实验中，抑制 β-amyloid (Aβ42)、Aβ38和Aβ40，其IC₅₀值分别为10.9 nM，12.0 nM和12.1 nM，并阻断与癌症（比如白血病）相关的Notch活化（抑制Notch信号通路），IC₅₀值为14.1 nM。

参考文献

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