The first chapter is a summary of recent publications about the effect of HNO in the cardiovascular system, detection of HNO in vitro, and physiological reactivity of HNO. The second chapter provides synthetic details of a newly developed method of a synthesis of HNO-Mb of high purity (> 95%). The transient absorbance studies of HNO-Mb revealed completely different results than that of other myoglobin adducts such as MbO2 and NO- Mb. Formation of the Mb-Fe(III)/HNO- geminate pair was confirmed by analyses of transient absorbance spectra at 395 nm. In the third chapter rate ...