Nitric oxide (NO) has been implicated in a wide range of biological functions in cluding vasodilation, airway relaxation, long-term potentiation, immunity, programmed cell death, and erectile function. Its biochemical mechanism of action, however, is poorly understood. The research effort in this laboratory is focused on elucidating NO-responsive signalling pathways in mammalian systems subject to redox control. Particular attention is given to the function-regulating interactions of NO with sulfhydryl centers in aminoacids, peptides and proteins. These (S-nitrosylation) reactions have provided insight into the mode of transport and targeting of NO in biological systems, the means by which its toxicity is mitigated, and its mechanism of regulation of diverse cellular functions. Ongoing efforts include studies on the cellular biology and biochemistry of NO in the cardiovascular system, lung, immune system, brain and skeletal muscle.