本酶催化的反应为Eliminative Cleavage Of (1->4)-alpha-D-Galacturonan Methyl Ester To Give Oligosaccharides With 4-Deoxy-6-O-Methyl-alpha-D-Galact-4-Enuronosyl Groups At Their Non-Reducing Ends,系统名称为(1->4)-6-O-Methyl-alpha-D-Galacturonan Lyase,更偏好果胶(甲酯)而不是果胶酸(阴离子,是EC 4.2.2.2 果胶酸裂解酶的首选底物)。去甲基化逐渐减慢其作用;然而,如果可切割键另一端的残基被甲基化,它仍然可以在去甲基化残基的任一侧切割。