CatalyCEST MRI with a diamagnetic CEST agent, 4-acedamido-2-(sulfoxy)benzoic acid, can detect the activity of sulfatase. An enzyme-responsive CEST signal was compared to an unresponsive CEST signal to determine a reaction coordinate of contrast agent cleavage by sulfatase. This imaging method produced parametric maps of CEST signal amplitudes and the reaction coordinates. Three isoforms of the enzyme were tested in biochemical solutions. catalyCEST MRI with the agent detected sulfatase activity in the media from sulfatase-expressing HEK293 cells but not in the media of sulfatase-deficient BT529 cells.