ABSTRACT
ABSTRACT: The interaction of camptothecin (CPT) with intravenous immunoglobulin (IVIG) was studied in vitro by fluorescence spectra, Fourier Transformation Infrared (FT-IR) spectra and molecular docking. The binding parameters calculated according to the Sips equation suggested that the binding of IVIG to CPT was a spontaneous entropy driven, non-specific and weak drug-protein interaction, characterized by two binding sites with the average anity constant Ko of 9.683 × 103 L·mol−1 at pH 4.0 and 310 K. The contents of secondary structural composition of free IVIG and its CPT complex were calculated by FT-IR dierence spectra, self-deconvolution, second derivative resolution enhancement and the curve-fitting procedure of amide I band, respectively. The observed spectral changes indicated a partial unfolding of the typical β structure of protein. Molecular docking was used to calculate the interaction mode between CPT with human IgG and the docking result of ∆Gº (−22.11 KJ·mol−1) was consistent with that of Sips method. IVIG can serve as a transport protein (carrier) for CPT.
