Nitroxyl (azanone) trapping by metalloporphyrins

Abstract The present review starts describing nitroxyl(azanone, 1 HNO) biological relevance, in relation with NO physiology, from a chemical reactivity perspective. After a description of commonly used azanone donors and their characteristics, the overlapping molecular targets of HNO and NO are presented with an emphasis on hememodels and proteins. We present also a brief description of metalloporphyrins and the main characteristics of their nitrosylcomplexes, and then describe the reactivity of azanone towards Fe, Ru, Mn and Co porphyrins, briefly mentioning hemeproteins, and focusing on 1 HNO trapping and its discrimination from NO. A comparison of reaction kinetics and/or nitrosylproduct stability with non- hememodels is also described. We illustrate the promiscuityof iron porphyrins, the stabilization properties of Ru and the discriminating behavior of Mn and Co porphyrins, which allows the design of optical and electrochemical selective 1 HNO sensors. Finally, a comparative analysis and future perspectives are presented, focusing on the in vivo reactivity of azanone and its putative endogenous production.