For example, fumarase catalyzes the interconversion of malic acid and fumaric acid. 如延胡羧酸酶能催化苹果酸和反丁烯二酸的可逆反应。
A new solid acid based on heteropolyacid has been proved to be a useful catalyst for the synthesis of dibutyl maleate. 新催化剂在顺丁烯二酸二丁酯的合成反应中显示很好的活性和温和的反应条件。