Raman Spectra of Isotope-substituted Mitochondria of Living Budding Yeast Cells: Possible Origin of the "Raman Spectroscopic Signature of Life"

Abstract

The (13)C and (2)H isotope Substitution effects have been examined for the "Raman spectroscopic signature of life," a mitochondrial Raman band at 1602 cm(-1) that sharply reflects the metabolic activity of living yeast cells. The band shifts to 1542 cm(-1) with (13)C substitution and to 1599 cm(-1) with (2)H substitution. Normal mode analysis based oil a DFT calculation suggests that it originates from a C=C double bond having no hydrogen atoms attached to the carbon atoms. The in-phase C=C stretch mode of ubisemiquinone radicals (CoQ and/or CoQH*) emerges as a strong candidate for the origin of the 1602 cm(-1) band.