Involved in the chlorophyll breakdown by its action in fluorescent chlorophyll catabolites (FCCs) demethylation (PubMed:22147518, PubMed:23723324, PubMed:24302623). Demethylates the C13(2)-carboxymethyl group present at the isocyclic ring of chlorophyll (PubMed:22147518). Uses primary fluorescent dioxobilin-type chlorophyll catabolite (pFDCC) as substrate to produce O13(4)-desmethyl pFDCC (PubMed:23723324, PubMed:24302623). Also able to catalyze pheophorbides in vitro (PubMed:22147518). Methylesterase shown to have carboxylesterase activity, methyl indole-3-acetic acid (MeIAA) esterase activity and methyl jasmonate (MeJA) esterase activity in vitro (PubMed:18467465, PubMed:27109476). H2O + methyl (indol-3-yl)acetate = (indol-3-yl)acetate + H(+) + methanol H2O + methyl (-)-jasmonate = H(+) + jasmonate + methanol H2O + primary fluorescent dioxobilin-type chlorophyll catabolite = H(+) + methanol + O13(4)-desmethyl pFDCC Plant hormone biosynthesis. Lipid metabolism; oxylipin biosynthesis. Porphyrin-containing compound metabolism; chlorophyll degradation. Accumulation of fluorescent chlorophyll catabolites (FCC) during senescence (PubMed:24302623). No effect on root length when grown in presence of exogenous MeIAA. Belongs to the AB hydrolase superfamily. Methylesterase family.