Plays an essential role in chain termination during de novo fatty acid synthesis. High thioesterase activity for lauroyl-ACP versus other acyl-ACPs. dodecanoyl-[ACP] + H2O = dodecanoate + H(+) + holo-[ACP] Forms homodimers. Expressed in developing cotyledons. Not detected in leaves. Introduced by genetic manipulation and expressed in canola by Monsanto (Calgene) so as to obtain laurate-rich seeds. Belongs to the acyl-ACP thioesterase family.