The 37 kDa cleavage product of caspase-2 generated within PC12 cells after serum deprivation corresponds to a caspase cleavage site at an aspartate residue. Lysates of PC12 cells prepared without serum deprivation were incubated with 60 U of ICE in a buffer containing 25 mm HEPES, pH 7.5, 10% sucrose, 0.1% CHAPS, and 10 mm DTT for the indicated times. The samples were subjected to Western immunoblotting using anti-N-Nedd at 1:250. In thelast lane, a lysate of PC12 cells prepared at 6 hr after serum deprivation was similarly subjected to Western immunoblotting on the same blot. The arrow indicates the N-terminal cleavage product.