Nitric oxide is reduced to HNO by proton-coupled nucleophilic attack (PCNA) by ascorbate, tyrosine, and other alcohols. A new route to HNO in biological media?

SUÁREZ, S. A.; NEUMAN, N.; MUÑOZ, M.; ALVAREZ, LUCIA; BIKIEL, D. E.; BRONDINO, C.; IVANOVIC-BURMAZOVIC, I.; MILJKOVIC, J.L.; FILIPOVIC, M.R.; MARTÍ, M. A; DOCTOROVICH, F.

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

AMER CHEMICAL SOC

Lugar: Washington; Año: 2015

0002-7863

ABSTRACT: The role of NO in biology is well established.However, an increasing body of evidence suggests that azanone(HNO), could also be involved in biological processes, some ofwhich are attributed to NO. In this context, one of the mostimportant and yet unanswered questions is whether and howHNO is produced in vivo. A possible route concerns thechemical or enzymatic reduction of NO. In the present work,we have taken advantage of a selective HNO sensing method,to show that NO is reduced to HNO by biologically relevantalcohols with moderate reducing capacity, such as ascorbate or tyrosine. The proposed mechanism involves a nucleophilic attackto NO by the alcohol, coupled to a proton transfer (PCNA: proton-coupled nucleophilic attack) and a subsequentdecomposition of the so-produced radical to yield HNO and an alkoxyl radical.