Activator of Rubisco, catalase, alcohol dehydrogenase and PEPcase are respectively

Mg2+ is an activator for both ribulose bisphosphate carboxylaseoxygenase and phosphoenol pyruvate carboxylase, both of which are critical enzymes in photosynthetic carbon fixation; Zn2+ is an activator of alcohol dehydrogenase and Fe activates catalase enzyme.