Carboxylesterase that acts as a key negative regulator of the Wnt signaling pathway by specifically mediating depalmitoleoylation of WNT proteins. Serine palmitoleoylation of WNT proteins is required for efficient binding to frizzled receptors. Functions in the prospective ectoderm and is required for neural induction. [Wnt protein]-O-(9Z)-hexadecenoyl-L-serine + H2O = (9Z)-hexadecenoate + [Wnt protein]-L-serine + H(+) Expressed in the egg and through cleavage to gastrulation stages. Enriched in the animal (prospective ectoderm) and dorsal regions in early gastrula. Shows a dynamic expression during embryogenesis, in particular during neural induction and antero-posterior (AP) patterning. Present in animal blastomeres at 4-cell and stage 6.5. At stages 8.5 and 9.5 (blastula), detected broadly in the animal region. At stage 10 (early gastrula), remains broadly expressed animally, but also detected in the dorsal marginal zone (the Organizer), with lower expression in the ventral marginal zone. At stage 11, found in the forming neural plate in a noticeable antero-posterior (AP) gradient (anterior high and posterior low), with additional weaker expression in the head mesoderm. Remains detectable, but becomes faint in the neural plate at stage 13. By stage 15, detected at the anterior border of the neural plate and in ventro-lateral epidermis excluding the neural plate. Later, it is detected in the cement gland (an anterior organ) at tail bud stages (stage 25), in branchial arches, the otic vesicle, and developing pronephros, with diffused expression in the head (stage 35). Belongs to the pectinacetylesterase family. Notum subfamily.