In subjects with obesity and hypertension, the activity of the antioxidant enzyme catalase was significantly decreased, 112.8 KU/mL (95.1–140.6 KU/mL), p = 0.02, contrary to what was found in subjects with obesity without arterial hypertension, 142.4 KU/mL (114.8–177.0 KU/mL). The gene discussed is CAT; the disease is hypertensive disorder.