Surface enhanced Raman spectroscopy (SERS) is a particularly attractive technique for the study of biomolecules due to signal enhancements of up to 1010, compared to that of non-enhanced Raman scattering. This magnitude of enhancement and lack of interference from water provides the rich spectral detail necessary for low concentration analytes in protein characterization. This study focuses on the characterization of polyphenol oxidase (PPO) and its substrate epinephrine. A previous spectrum of epinephrine has been reported but lacks detail and relevant peaks for substrate identification; no previous spectra have been reported for PPO. SERS and Raman spectra are reported with assignments for each. The PPO spectrum consists of amino acid residues consisting of tyrosine, tryptophan, cystine, and phenylalanine. Relative intensities of vibrations at 1306, 1391, 1589, and the 600-970 cm-1 range allowed for determination of the favorable orientation of epinephrine complexed to the silver nanoparticle surface. This assignment was made through selective enhancement comparison between reported SERS and Raman spectra.

Raman and surface-enhanced Raman scattering of polyphenol oxidase and epinephrine on silver nanoparticles

243rd National Meeting (2012)

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