Part I: surface-enhanced Raman spectroscopy investigation of amino acids and their homodipeptides adsorbed on colloidal silver

• Published in: Applied spectroscopy Vol. 58; no. 5; p. 570
• Main Authors: Podstawka, Edyta, Ozaki, Yukihiro, Proniewicz, Leonard M
• Format: Journal Article
• Language: English
• Published: United States 01.05.2004
• Subjects: Adsorption; Amino Acids - analysis; Amino Acids - chemistry; Binding Sites; Colloids - chemistry; Dimerization; Dipeptides - analysis; Dipeptides - chemistry; Protein Binding; Protein Conformation; Reproducibility of Results; Sensitivity and Specificity; Silver - chemistry; Spectrum Analysis, Raman - methods; Surface Plasmon Resonance - methods
• ISSN: 0003-7028
• DOI: 10.1366/000370204774103408

Surface-enhanced Raman scattering spectra (SERS) were measured for various amino acids: L-methionine (Met), L-cysteine (Cys), Lglycine (Gly), L-leucine (Leu), L-phenylalanine (Phe), and L-proline (Pro) and their homodipeptides (Met-Met, Cys-Cys, Gly-Gly, LeuLeu, Phe-Phe, and Pro-Pro) in silver colloidal solutions. The geometry and orientation of the amino acids or dipeptides on the silver surface, and their specific interaction with the surface, were deducted by detailed spectral analysis of the SERS spectra. This analysis has allowed us to propose the particular surface geometry of amino acids or dipeptides and also implied that C-C bonds were almost parallel to the surface, as evidenced by the absence of marker bands in the skeletal C-C stretching region of the spectra. Additionally, using "time-dependent" SERS measurements we solved an existing controversy regarding the binding specificity of Gly-Gly on the silver surface.