1219012-65-3Relevant articles and documents
Antithyroid drugs and their analogues protect against peroxynitritemediated protein tyrosine nitration-a mechanistic study
Bhabak, Krishna P.,Mugesh, Govindasamy
, p. 1175 - 1185 (2010)
In this paper, the effect of some commonly used antithyroid drugs and their analogues on peroxynitritemediated nitration of proteins is described. The nitration of tyrosine residues in bovine serum albumin (BSA) and cytochrome c was studied by Western blot analysis. These studies reveal that the antithyroid drugs methimazole (MMI), 6-n-propyl-2-thiouracil (PTU), and 6-methyl-2- thiouracil (MTU), which contain thione moieties, significantly reduce the tyrosine nitration of both BSA and cytochrome c. While MMI exhibits good peroxynitrite (PN) scavenging activity, the thiouracil com-pounds PTU and MTU are slightly less effective than MMI. The S- and Semethylated compounds show a weak inhibitory effect in the nitration of tyrosine, indicating that the presence of a thione or selone moiety is important for an efficient inhibition. Similarly, the replacement of N-H moiety in MMI by N-methyl or N-m-methoxybenzyl substituents dramatically reduces the antioxidant activity of the parent com-pound. Theoretical studies indicate that the substitution of N-H moiety by NMe significantly increases the energy required for the oxidation of sulfur center by PN. However, such substitution in the selenium analogue of MMI increases the activity of parent compound. This is due to the facile oxidation of the selone moiety to the corresponding selenenic and seleninic acids. Unlike N,N'-disubstituted thiones, the corresponding selones efficiently scavenge PN, as they predominantly exist in their zwitterionic forms in which the selenium atom carries a large negative charge.
