Chemical characterization of Endomorphine-TAMRA conjugates.

(A) Chemical structure of EM-TAMRA indicated by modified Endomorphine-1 peptide in blue and TAMRA-Maleimide in magenta. Absorbance and Emission spectra of (B) 200 μM TAMRA-Maleimide and (C) 20 μM EM-TAMRA at pH 7.24. (D) Absorbance of 20 μM EM-TAMRA at different pH 2.15–10. INormalized = Normalized intensity; Iabs = Normalized absorbance.