We list a few other sources you may want to consider, like Invitrogen's (ThermoFisher) mAb 31A1067:

https://www.linscottsdirectory.com/antibodies?q=caspase-3-active-pro

Also, there are a couple of reviews you should look at on www.pAbmAbs.com

Good luck.

Thanks Russell.

The quality of antibody affect a lot to the WB result, you should try some high quality commercial antibody. 

I fund some product for you to consider:

http://www.creative-diagnostics.com/Search.aspx?keys=caspase-3&cid=4

or if you don't care about the price, you could consider antibody from Abcam.

Hope it can help.

Thanks Yudong