The research will involve the generation and solution reactivity of nitroxyl (HNO), which has recently received significant attention, especially as a potential alternative to current treatments of cardiac failure. Due to its inherent reactivity, HNO must be generated in situ, but only a very limited number of appropriate precursors currently exist. Adding to the difficulty of studying HNO chemistry is that a viable method for its direct detection in solution or biologically relevant preparations is not currently available. To address current deficiencies in the understanding of HNO chemistry and biochemistry, in available HNO donor molecules, and in practically useful direct HNO detection techniques, the proposed research will develop (1) new physiologically useful thermal precursors to HNO, (2) new photochemical precursors to HNO suitable for nanosecond time-resolved infrared (TRIR) investigations, and (3) new analytical tools for its detection and study in aqueous solutions. The development of new HNO donors, combined with reactivity studies and the evaluation of HNO-induced protein modifications, will not only provide fundamental insight into the biological activity of HNO, but may also ultimately lead to the development of a new class of compounds for the treatment of heart failure. In addition, proposed research on the development of new thermal and photochemical precursors to HNO, new analytical tools for its detection, and elucidation of HNO-induced modifications of PLN will afford broad training for graduate students and undergraduates. Undergraduate participation in research will continue to be actively encouraged.
, which has recently received significant attention, especially as a potential alternative to current treatments of cardiac failure. Due to its inherent reactivity, HNO must be generated in situ, but only a very limited number of appropriate precursors currently exist. Adding to the difficulty of studying HNO chemistry is that a viable method for its direct detection in solution or biologically relevant preparations is not currently available. To address current deficiencies in the understanding of HNO chemistry and biochemistry, in available HNO donor molecules, and in practically useful direct HNO detection techniques, we have developed (1) new physiologically useful thermal precursors to HNO, (2) new photochemical precursors to HNO suitable for nanosecond time-resolved infrared (TRIR) investigations, and (3) new analytical tools for its detection and study in aqueous solutions. In addition, research has addressed the HNO-induced modifications of the protein, phospholamban (PLN), which is involved in regulating the cardiac sarcoplasmic reticulum calcium pump (SERCA2a), to determine the mechanism by which HNO enhances SERCA2a activity. We have examined model cysteine-containing peptides and have found that the reactivity of sulfinamides (generated from the reaction of thiols with HNO) within a peptide is different from simple non-peptidic sulfinamides. Although it has generally been assumed that this thiol to sulfinamide modification is irreversible, we have shown that sulfinamides can be reduced back to the free thiol in the presence of excess thiol at physiological pH and temperature.
