本酶催化的反应为2-Phospho-4-(Cytidine 5'-Diphospho)-2-C-Methyl-D-Erythritol = 2-C-Methyl-D-Erythritol 2,4-Cyclodiphosphate + CMP,系统名称为2-Phospho-4-(Cytidine 5'-Diphospho)-2-C-Methyl-D-Erythritol CMP-Lyase (Cyclizing; 2-C-Methyl-D-Erythritol 2,4-Cyclodiphosphate-Forming),来自大肠杆菌(Escherichia coli)的酶需要Mg2+或Mn2+。构成萜类生物合成的非甲羟戊酸替代途径的一部分(图示见
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