Protein kinases have the ability to phosphorylate tyrosine residues of other proteins and play prominent roles in the regulation of normal cell growth, as well as tumor growth. In this experiment, we identified marker bands that would be used as indicators of protein kinase-inhibitor binding. Good candidates are the phosphate group modes on phosphotyrosine and the ring modes of pentafluorophenylalanine. Fourier-Transform infrared (FTIR) marker bands for pentafluorophenylalanine are at 960, 1527 and 1510 cm-1. To help us analysis our results we did some Gaussian 03 ab initio calculations, we verified that the bands correspond to the C-F modes on the aromatic ring. The FTIR marker band found for phosphotyrosine was at 930 cm-1. Again using Gaussian simulations, we verified that this band belongs to the phosphate functional group. Solvent dependence studies of these amino acids were also performed. Our results indicate that when dissolved in different solvents, the marker bands determined for pentafluorophenylalanine and phosphotyrosine are still visible and are slightly shifted. Data were discussed in terms of the viability of these modes as marker for studying Src Kinase-Inhibitor interactions.