caspase-3 和Cleaved-caspase-3 区别在于：
caspase-3切割（cleaved）活化之后就会变成Cleaved-caspase-3 ，即后者是前者的活化形式。
如果你要检测凋亡率的话，可以买cleaved-caspase-3。需要留意的是：如果做WB，有些caspase-3的抗体是可以同时检测Cleaved-caspase-3 的。 

我觉得应该说是形成多聚体后才能叫做活化吧，如果你单纯的剪切的亚单位只能叫做成熟.如果他们不能形成多聚体是不能发挥作用的！

an Activated Form of Caspase-3：Caspase-3 is activated by cleavage events at Asp-28/Ser-29 (between N-terminal pro-domain) and Asp-175/Ser-176 (between large and small subunits) to generate a large subunit of 17-kDa and a small subunit of 12-kDa .

The caspase-3 precursor is first cleaved at Asp 175-Ser 176 to produce the p11 subunit and the p20 peptide. Subsequently, the p20 peptide is cleaved at Asp 28-Ser 29 to generate the mature p17 subunit.The active caspase-3 enzyme is a heterodimer composed of two p17 and two p11 subunits.