label: 4-O-methyl-alpha-D-glucuronate derivative + an alcohol + H(+) => a 4-O-methyl-alpha-D-glucuronosyl ester derivative + H2O
label_lc: 4-o-methyl-alpha-d-glucuronate derivative + an alcohol + h(+) => a 4-o-methyl-alpha-d-glucuronosyl ester derivative + h2o