Carboxylesterase involved in the biosynthesis of the benzylisoquinoline alkaloid noscapine (PubMed:25485687, PubMed:27378283, PubMed:29610307). Converts 3-O-acetylpapaveroxine to papaveroxine which spontaneously rearranges to narcotine hemiacetal (PubMed:25485687, PubMed:27378283). 3-O-acetylpapaveroxine + H2O = acetate + H(+) + narcotine hemiacetal Alkaloid biosynthesis. Belongs to the 'GDXG' lipolytic enzyme family.