Moreover, zinc-inducible metallothionein is an effective scavenger for peroxynitrite-derived radicals—which, in diabetics, promote uncoupling of endothelial nitric oxide synthase by oxidizing its cofactor tetrahydrobiopterin, thereby boosting superoxide generation and impairing the nitric oxide generation vital for vascular health [63,64,65,66,67,68]. Here, NOS3 is linked to diabetes mellitus.