CAT and endothelial dysfunction: For example, low molecular weight SOD and catalase mimetics are highly effective at catalyzing the transformation of superoxide and hydrogen peroxide [24]; however, tempol, a SOD mimetic, can reverse endothelial dysfunction in diabetic rats [25], and FP15, a peroxynitrite decomposition catalyst, has been reported to protect against both leukocyte adhesion within retinal vessels and vascular dysfunction in diabetic mice [26].