Pectin methylesterase (PME) inhibitor that can target PME3 in a pH-dependent manner, mainly in slightly acidic conditions (pH 6.0 and 5.0) but not at pH 7.0; this processus relies on changes in the protonation of amino acids involved in intermolecular and intramolecular interactions (PubMed:26183897, PubMed:29109147). Regulates homogalacturonan methylesterification during plant development (PubMed:26183897).