TAT-Gap19(I130A) is a control peptide for TAT-Gap19, a Cx43 hemichannel blocker. TAT-Gap19(I130A) consists of TAT-GAP19 with a I130A amino acid residue change at a key residue for GAP19 activity. In C6 glioma cells expression Cx43, TAT-GAP19(1130A) does not inhibit [Ca2+]i-triggered ATP release at 200 μM. TAT-Gap19(I130A) is cell permeable.