Methylesterase that efficiently and specifically hydrolyzes methyl indole-3-acetic acid (MeIAA) to IAA (auxin). MeIAA is believed to be an inactive form of auxin that needs to be demethylated to exert a biological effect. H2O + methyl (indol-3-yl)acetate = (indol-3-yl)acetate + H(+) + methanol kcat is 0.18 sec(-1) with methyl indole-3-acetic acid as substrate. Plant hormone biosynthesis. Expressed in several tissues of seedlings and adult plants, with a higher relative level of expression in the seedling shoot apex and the adult stem. Longer hypocotyls when grown in presence of exogenous MeIAA. Belongs to the AB hydrolase superfamily. Methylesterase family.