Bid BH3 is a pro-apoptotic member of the 'BH3-only' subset of BCL-2 family proteins that constitute a critical control point in apoptosis. BID BH3 interacts with Bax to induce mitochondrial outer membrane permeabilization in the apoptotic process. This peptide contains 8 Arg residues in the L-isomeric form on the N-terminus. BID Tagging with poly-arginine facilitates cell internalization. R8BIDH3 has been shown to induce apoptosis of Jurkat leukemia cells in vitro.