Peroxynitrite　is　a　potent　oxidant　to　nitrate　tyrosine　of　protein,　induce　DNA　strand　breaks　and　promote　the　lipid　peroxidation　in　vivo,　which　can　result　in　serious　diseases,　such　as　cardiopathy,　neurodegenerative　disorders　and　even　cancer.　However,　carbon　dioxide　can　react　with　peroxynitrite　and　change　the　toxicological　properties　of　peroxynitrite,　which　is　in　equilibrium　with　bicarbonate　anion　in　the　extracellular　milieu　(25　mM　in　plasma).　Due　to　reaction　mechanisms　of　peroxynitrite　with　amino　acids　are　the　bases　to　explore　the　damage　of　protein　induced　by　peroxynitrite.　Here,　by　using　stopped　flow　instrument,　UV-visible　spectra,　fluorescence　spectroscopy　and　high　performance　liquid　chromatography,　we　investigated　the　kinetics　reaction　of　carbon　dioxide　and　peroxynitrite　in　the　different　environment　and　the　effects　of　carbon　dioxide　on　damage　of　amino　acids　caused　by　peroxynitrite.　The　results　showed　when　the　temperature　was　37°C　and　pH　7.4,　two-order　rate　constant　of　peroxynitrite　react　with　NaHCO3　was　2.3×103　M-1·s-1.　The　damage　of　amino　acids　aroused　by　peroxynitrite　was　weakened　in　0.1　M　phosphate　buffer　solution　with　25　mM　NaHCO3　and　the　damage　inhibition　ratio　of　tryptophan　and　tyrosine　reached　to　27%　and　50%,　respectively.　Moreover,　carbon　dioxide　could　also　reduce　the　fluorescence　quenching　of　tyrosine　induced　by　peroxynitrite.