Enzyme system generation of singlet (1.DELTA.g) molecular oxygen observed directly by 1.0-1.8-.mu. luminescence spectroscopy

Abstract

The observation of a strong singlet molecular oxygen luminescence emission in the ir produced in the decomposition of hydrogen peroxide by the enzymes lactoperoxidase, catalase, and chloroperoxidase is reported. A mixture of H/sub 2/O and D/sub 2/O was used as a reaction media. The luminescence emission spectra of the lactoperoxidase/H/sub 2/O/sub 2/ and chloroperoxidase/H/sub 2/O/sub 2/ were found to exhibit a single emission band at 1.28 ..mu..m for the former and three bands for the latter - a strong band at 1.30 ..mu..m and a possible weak band extending from the long-wavelength edge of the monochromator at 1.60 to 1.45 ..mu..m. The peak at 1.28 ..mu..m is absent in the catalase/H/sub 2/O/sub 2/ spectrum, but the peak at 1.64 ..mu..m is very evident. The spectra are interpreted as indicating the generation of free singlet oxygen (peak at 1.28 and 1.30 ..mu..m) in the case of the first two enzymes/H/sub 2/O/sub 2/ systems and the generation of predominately bound singlet molecular oxygen in the case of catalase/H/sub 2/O/sub 2/.