Also catalyses the formation of the methyl monoester of cis-aconitate, isocitrate and citrate, but more slowly. While the enzyme from Saccharomyces cerevisiae forms (E)-2-(methoxycarbonylmethyl)butenedioate as the product, that from Escherichia coli forms (E)-3-(methoxycarbonyl)-pent-2-enedioate and is therefore classified as a separate enzyme (cf. EC 2.1.1.144, trans-aconitate 2-methyltransferase).
